Arawak OS/2 Shareware/PAKLED.ISO/docs/os2perf.inf

OS/2 Help File | 1993-07-09 | 119.9 KB | 3,877 lines

ΓòÉΓòÉΓòÉ 1. Version Notice ΓòÉΓòÉΓòÉ

Information

Copyright International Business Machines Corporation 1993. All rights
reserved.
Note to U.S. Government Users Ч Documentation related to restricted rights Ч
Use, duplication or disclosure is subject to restrictions set forth in GSA ADP
Schedule Contract with IBM Corp.


ΓòÉΓòÉΓòÉ 2. Preface ΓòÉΓòÉΓòÉ

This Performance White Paper is designed to assist end users in improving the
performance of their OS/2 system by providing information on software and
hardware. Items addressed include software tuning and hardware upgrades. It was
written by the OS/2 System Performance Department members (IBM Boca Raton),
with contributions from the OS/2 operating system development community.

There are many questions on what to do to increase the overall performance of
an OS/2 system. This is a complicated question as various factors influence the
performance of OS/2. This article attempts to provide information, from various
sources, that relates to the performance of OS/2 2.1. Other articles, press
releases, product information guides and independent testing all contributed to
the information found here. Several of these documents are listed here.

o OS/2 2.1 Using the Operating System
o The OS/2 V2.1 Update Redbook
o OS/2 2.0 Installation & Tuning Guide (GG24-3948)
o OS/2 2.0 Information and Planning Guide (G326-0160)
o OS/2 Version 2.0 Technical Compendium (GGOF-2254)
o Volume 2: DOS and Windows Environment (GG24-3731)
o Volume 4: Application Development (GG24-3774)
o Volume 5: Print Subsystem (GG24-3775)

The information in this paper deals directly with stand-alone systems. This is
not to say that the information will not prove useful to the networked system,
but it does not deal with networked systems or the hardware used for
networking.


ΓòÉΓòÉΓòÉ 3. Trademarks referenced ΓòÉΓòÉΓòÉ

The following products are referenced in the document:

o OS/2, Personal Systems/2, PS/2 and Micro Channel are registered trademarks of
  the International Business Machines Corporation
o Presentation Manager, WIN-OS/2 and SPM/2 are trademarks of the International
  Business Machines Corporation
o Microsoft and Microsoft Windows are registered trademarks of Microsoft
  Corporation
o Intel is a registered trademark of Intel Corporation
o Pentium is a trademark of Intel Corporation
o R:Base is a trademark of Microrim, Inc.
o Norton Disk Utitilies is a trademark of Symantec Corporation
o Microsoft Word and Word for Windows are registered trademarks of Microsoft
  Corporation
o WordPerfect is a trademark of Wordperfect Corporation
o Performance 2.1 is a trademark of Clear and Simple, Inc.
o Lotus and 1-2-3 are registered trademarks of Lotus Development Corp.
o FoxPro is a trademark of Microsoft Corporation
o Video Seven is a trademark of Headland Technology Inc.


ΓòÉΓòÉΓòÉ 4. Why OS/2 Version 2.X ? ΓòÉΓòÉΓòÉ

The general advantages of the 32-bit version of OS/2 are the flat memory model,
exploitation of new hardware, increased programming model support, multiple
virtual DOS machine sessions, and relief of some system limits.

The flat memory model is possible due to built in function on the 80386SX and
higher processors. This allows for a very large ( 4 Gigabyte ) single address
space referred to as flat memory. Call/return times are reduced by eliminating
the need to switch segments. Internal calls are handled with the 32-bit offset
rather than the segment:offset used previously. The implementation of this
model allows OS/2 2.x to have 32-bit APIs. While all previous 16-bit APIs are
still completely supported, many APIs are now 32-bit, thus improving
performance and enhancing function.

OS/2 2.x exploits hardware in several ways. The OS/2 2.x operating system
exploits the Intel 80386 and 80486 microprocessor capabilities. OS/2 2.x
utilizes native protected mode and virtual 8086 mode, memory virtualization via
a flat memory model, and paging. Utilizing the 32-bit native mode of the 80386
and 80486 facilitates the exploitation of 32-bit arithmetic and move
instructions. These hardware platforms provide additional segment registers and
extend the general registers to 32-bits. When applications are developed for
this environment, proper design decisions will result in superior performing
programs.

OS/2 2.x also provides support for advanced disk hardware. It can use request
lists to move data to the disk, where the hardware supports scatter/gather, and
simulates this for disk drives that do not. This improves the performance of
disk accesses.

OS/2 provides support for advanced parallel port hardware. If the machine
supports Micro Channel and uses Direct Memory Access (DMA) for its parallel
port, then OS/2's Print Device Driver significantly improves the speed data is
sent to the printer (in excess of 100 kilobytes per second). This support
allows OS/2 to improve performance of applications since OS/2 can spend more
time running applications and less time handling interrupts.

OS/2 2.x releases support all existing 16-bit OS/2 applications (VIO or
Presentation Manager), 32-bit OS/2 Presentation Manager applications and mixed
model OS/2 applications in the OS/2 full screen or windowed sessions. OS/2 2.x
also supports most DOS applications including those applications that use EMS,
XMS or DPMI memory in the VDM full screen or windowed sessions. OS/2 2.0
supported most 2.x and 3.0 Windows applications in the WIN-OS/2 full screen
session and in the WIN-OS/2 seamless session on VGA systems. OS/2 2.01 provided
the same support as release 2.0, but added seamless support for the Tseng and
IBM VGA 256c chip sets. OS/2 2.1 supports the Windows 3.0 and 3.1 applications,
and Windows 2.x applications that do not require real mode, in WIN-OS/2 full
screen and seamless sessions on VGA, XGA and SVGA systems (8514 seamless
support is not available in OS/2 2.1).

MVDM (Multiple Virtual DOS Machines) sessions allow for a more fully integrated
system. When the DOS sessions are virtualized, there can be multiple sessions
concurrently. OS/2 2.x supports up to 255 concurrent sessions, although
hardware limitations generally prevent you from reaching that total. DOS
sessions can also be windowed. Utilizing the processor's native virtual 8086
mode eliminated the need to switch from real to protect mode thus improving
performance. The virtual DOS sessions can execute in the background, without
having to suspend execution of the current application. This allows DOS
applications access to the system clipboard, allowing cut and paste functions
between other windowed sessions.

The Virtual DOS Machine (VDM) sessions support several types of memory:

o Extended Memory (XMS) to 16 Megabytes

o Expanded Memory (EMS) to 32 Megabytes

o DOS Protect Mode Interface (DPMI) Memory to 512 Megabytes

Generally, VDM sessions support the execution of most DOS applications. There
are some DOS applications and products that cannot be supported by DOS
emulation due to the nature of the emulation code and the multitasking and
protection demands of OS/2 version 2.x.

Windows application support is included in OS/2 2.x to allow execution of
Windows applications along with OS/2 and DOS applications, providing a wide
range of application support.

Windows application support has been enhanced in OS/2 2.1. Enhancements were
provided in OS/2 2.1 to support the Windows 3.1 environment for running Windows
applications full screen and seamlessly on the OS/2 Workplace Shell. The Adobe
Type Manager support has moved to version 2.5. The performance of WIN-OS/2 has
also been substantially improved. A new mode called Enhanced Compatibility Mode
enables a number of Windows 3.1 enhanced mode applications to run. The
Clipboard and DDE support have been redesigned for speed, and several
enhancements were made to display drivers. The 2.x versions of OS/2 also
utilize the object oriented Workplace Shell which provides a friendlier user
interface (for example the drag/drop function for direct manipulation of
objects).


ΓòÉΓòÉΓòÉ 5. What hardware do I need to run OS/2 ? ΓòÉΓòÉΓòÉ

This section covers hardware and support requirements for the OS/2 2.x
operating system. To help you plan user configurations, worksheets are provided
that include memory and hard disk requirements for specific components and
features.


ΓòÉΓòÉΓòÉ 5.1. What hardware configurations run OS/2 2.0 & 2.1 ? ΓòÉΓòÉΓòÉ

OS/2 2.0 is designed for personal computers with the following minimum
requirements:

o Intel (or compatible) 80386SX microprocessor
o 4MB of memory (6MB or more recommended)
o 60MB hard disk with 15-30MB of free disk space  (ver. 2.0 & 2.01) or 20-40MB
  of free disk space  (ver. 2.1)
o 2-button mouse or other pointing device

Beginning in OS/2 version 2.1, you can install Windows support on a partition
different from the partition where OS/2 is installed. This will allow you to
move some of the disk space requirement to another partition. While you will
still need the same amount of disk space in total, this feature allows
flexibility when available space on the install partition is limited. Because
of its 32-bit addressing power, the OS/2 2.x operating system requires a
computer that has a system unit equipped with an Intel (or compatible) 80386
(or higher) microprocessor. The 80386SX microprocessor provides fair
performance for those who work in lower-demand application environments. In
environments that demand multiple concurrent processes, the 80486 will provide
excellent performance. Also consider the 80486 series if you expect to switch
frequently and rapidly among a large number of concurrent tasks.


ΓòÉΓòÉΓòÉ 5.2. How much system memory is needed ? ΓòÉΓòÉΓòÉ

Topics that follow discuss memory and disk storage information that you need to
consider for OS/2 2.0 and OS/2 2.1. Memory and disk storage are closely related
because of the ability of the operating system to manage the allocation of
memory resources between real physical memory and hard disk space.

The minimum memory requirement for OS/2 2.0 & 2.1 is 4MB. Some computers use up
to 128KB for ROM-to-RAM (read-only memory to random-access memory) remapping;
some use more than 128KB for other hardware purposes. Therefore less than the
minimum required memory is available. On these systems, another 512KB to 1MB
would satisfy the minimum requirement. You can check such systems to see if
there is a way to replace the memory so that the minimum requirement is met.

In general, the OS/2 2.0 & 2.1 operating system, including its shell, requires
1 to 2 megabytes more memory to give performance equivalent to OS/2 version
1.3. The memory requirement for OS/2 2.1 is similar to the memory requirement
for OS/2 2.0. It is recommended that systems have a minimum of 6 megabytes of
memory for good performance.


ΓòÉΓòÉΓòÉ 6. What performance improvements were made in ver. 2.1 ? ΓòÉΓòÉΓòÉ

The most significant performance improvements made between version 2.0 and 2.1
were in WIN-OS/2. Additional improvements were made in the graphics sub-system,
VDM support, and printing.

A significant enhancement provided in OS/2 2.1 is the support of a Windows 3.1
environment to run Windows applications seamlessly on the Workplace Shell. The
performance of WIN-OS/2 has been substantially improved. A new mode called
Enhanced Compatibility Mode enables a number of Windows 3.1 enhanced mode
applications to run. The Clipboard and DDE underwent a major redesign,
including virtual rendering of clipboard data. Several enhancements were made
to the WIN-OS/2 display drivers.

In OS/2 2.0, support was provided in WIN-OS/2 3.0 to enable Windows 3.0
applications to run in Standard and Real modes. In OS/2 2.1, the support has
been upgraded to include device drivers written specifically to run in the
Windows 3.1 environment, including XGA / XGA-2 and SVGA support.

In OS/2 2.1, the graphics engine was rewritten (from assembler) using the
32-bit IBM C Set/2 compiler. In addition to being a fully 32-bit engine, many
graphics operations were enhanced for better performance. The 32-bit engine
consumes more memory than the 16-bit version, so efforts were made to optimize
its memory usage for both the Workplace Shell and graphical intensive
application environments. Frequently used routines in the graphics engine were
tuned and linked together in such a way as to minimize the system working set.
This process is referred to as page tuning.

In addition to the graphics engine, the PM display drivers have changed
significantly between OS/2 version 2.0 and OS/2 version 2.1. The OS/2 2.1 PM
XGA driver makes use of the new hardware features of the latest XGA-2 display
adapter. It provides non-interlace support, takes advantage of external polling
capabilities, and can display up to 64K colors in low resolution modes (640 x
480, 640 x 400). The XGA PM display driver is 32-bit, and performance has
improved. There were no SVGA display drivers supplied in OS/2 2.0. In OS/2 2.1,
several SVGA chip sets are supported. The SVGA PM display drivers are all
32-bit and 256 colors. Performance comparisons between OS/2 2.1 and OS/2 2.0
with generic 16-bit drivers from vendors show that OS/2 2.1 SVGA performance is
visibly faster. The OS/2 2.1 PM VGA driver is 32-bit. From the viewpoint of
performance, it has some improvement over the 16-bit version. The 8514 PM
display driver with OS/2 2.1 is now 32-bit. Since the graphics engine is also
32-bit, performance has improved.

Dual-thread support was added to VDMs in release 2.1. OS/2 enhanced its
multimedia support by providing the dual-thread feature. Real time
applications, such as multimedia and communications, need to handle interrupts
while doing file I/O. System timer ticks are used to update the screen and
produce sound. In the first release of OS/2 2.0, each VDM executes as one
thread. If the thread is busy doing a file I/O operation, it does not receive
an interrupt until the entire I/O operation is complete. By introducing a
second thread, OS/2 2.1 allows interrupts to be serviced while waiting for the
completion of the I/O operation. This improves the performance of multimedia
DOS applications, which need interrupt notification even when doing file I/O.
DOS communication programs that do file I/O may be helped by this feature.

This version of OS/2 also contains some Pentium specific optimizations. The
areas where this enablement was added improved the performance in interrupt
management for VDMs and improved floating point performance in VDM and WIN-OS/2
sessions.

DPMI is a protected mode programming interface for DOS applications, allowing
those applications to run on the 80x86 processors in protect mode, while
utilizing the real mode services of the operating system and device drivers. In
OS/2 2.1 the DPMI support has been upgraded to version 1.0.

OS/2 2.1 also performs better running DOS and Windows communication
applications. OS/2 2.1 also supports more DOS communication applications.

Performance improvements were made for printing. OS/2 now ships a 32-bit
PostScript printer driver. For parallel ports LPT1 to LPT3, both parallel port
device drivers, PRINT02. SYS for Micro Channel machines and PRINT01. SYS for
AT-Bus (ISA) and EISA machines, send data faster in OS/2 2.1. This allows the
print buffer found on most printers, to be filled quickly reducing the overall
print job time. There are also printer properties that improve performance and
the OS/2 spooler's print priority can be changed if needed.

On laptops that support the Advanced Power Management 1.0 Specification, there
is an improvement in battery life. Software support will automatically be
installed on systems with the correct hardware support. The object icon can be
found in the System Setup folder. This object is used to show the current
status/state of your laptop's battery and allows you, if you wish, to turn the
advanced power management functions on and off.


ΓòÉΓòÉΓòÉ 7. What should I know to install OS/2 2.1? ΓòÉΓòÉΓòÉ

The purpose of this document is to help you tune your OS/2 2.1 system. This
section follows the installation path to provide performance related
information for the end user. You can use this section for information relating
to system performance as you complete your installation. Additional sections
contain information for tuning installed systems that can be used after you
complete installation or on preinstalled systems.

The first screen that requires your input asks if you accept the partition
selected by install for your system installation. The choices are accept the
partition or select another partition. Accepting the default will install OS/2
on the C: Primary partition or the partition set installable (having a
partition set installable requires you to have run FDISK earlier). If you have
a new hard disk (not preinstalled), accepting the default creates one primary
partition the total size of your hard drive.

If you decide to select another partition, installation puts you in FDISK and
you can make changes as needed. There are several topics that interact here --
use of the Boot Manager, partition sizes and which file system to use. They are
discussed here so that you may understand the implications of your selections.


ΓòÉΓòÉΓòÉ 7.1. Boot Manager ΓòÉΓòÉΓòÉ

You should consider the use of the Boot Manager facility that is provided with
OS/2 2.0 and 2.1. This facility allows you to have multiple operating systems
installed on your computer system and then select which one to make active and
boot from. This is very helpful when migrating from one operating system to
another, such as DOS/Windows to OS/2, or when upgrading to new versions of an
operating system, such as OS/2 1.3 to OS/2 2.0 or 2.1. This allows you to test
the new system, while maintaining your old system.

In order to use this feature, you will require enough space on your disk for
the multiple operating systems, as well as 1 MB for the Boot Manager facility
itself. The 1 MB for the Boot Manager must be space which is not allocated to
any disk partition, and can be loaded at the beginning or the end of the
physical disk drive. It is recommended that you place the Boot Manager
partition at the end of the disk drive so that you will not have to seek over
it all the time. The Boot Manager partition is only used when you boot up your
system, or when you change the Boot Manager options, so there are no
performance impacts by having it at the end of the drive.

If you do not have the free space to use the Boot Manager, see the next
section, "Partitioning Your Hard Disk" for further information and some helpful
suggestions.

To install the Boot manager, you must use the FDISK utility that is supplied
with OS/2 2.0 or 2.1. This is located on Diskette 1 of the installation
diskettes. It can be run either from an OS/2 1.3 system or an OS/2 2.X system.
It will not run from a DOS session. When you start FDISK, it will show you the
partitions that are defined on the first disk. You can use the TAB key to go to
the top of the screen to select which disk you want to work with. Use the Tab
key again to go to the Partition Information portion of the screen. When you
hit the Enter key for the partition that is highlighted, you are presented with
a menu list. Consult the Installation Guide for information on using FDISK, or
refer to FDISK and SETBOOT options in the on line help facility.


ΓòÉΓòÉΓòÉ 7.2. Partitioning Your Hard Disk ΓòÉΓòÉΓòÉ

Partitioning a system is truly individualistic. Just like background screen
colors and bit-maps, there are endless variations available when partitioning
your hard drive. The size of the hard drive and planned use of the system
affects your decision. Lets use Jane and her systems at home and at work as an
example. Her system at work is connected to a LAN and a host system. Her system
at home is primarily stand-alone. Her system at work (400 MB hard disk) is
partitioned as:

Figure 1. Partitioning Example #1


  C: (Primary Partition)  50 MB formatted FAT

  D: (Logical Partition)  80 MB formatted FAT

  E: (Logical Partition) 269 MB formatted HPFS

  (Boot Manager) 1 MB

The smaller partitions are formatted FAT, while the large partition (containing
her OS/2 applica- tions and swap file) is formatted HPFS for better
performance. The C: partition has OS/2 2.0 installed and the D: partition has
OS/2 2.1 installed. Having C: and D: contain two versions of OS/2 allows her to
boot between them as needed for development and testing.

Another example is her system at home (400 MB hard drive). It is partitioned
as:

  Figure 2. Partitioning Example #2

  C: (Primary Partition)  30 MB formatted FAT

  D: (Logical Partition)  50 MB formatted FAT

  E: (Logical Partition) 140 MB formatted HPFS

  F: (Logical Partition) 100 MB formatted FAT

  G: (Logical Partition)  79 MB formatted FAT

  (Boot Manager) 1 MB

Again, the smaller partitions are formatted FAT, while the large partition is
formatted HPFS for better performance. The C: partition has DOS 4.0 installed
with Windows 3.1. The D: partition has OS/2 2.0 installed, and F: has OS/2 2.1
installed. She would have installed 2.1 in D: except that she found that many
Windows applications like to install themselves on the same drive as Windows
code, and she was running tight on disk space on D:. F: is formatted FAT
because it contains Windows applications that are sometimes run when DOS is
booted. The E: partition contains her OS/2 applications, data and the OS/2 swap
file. The G: partition holds her children's games and the FAT format allows
them to be run from OS/2 or DOS.

Originally, this system did not have boot manager installed. When she decided
to install it, she needed a 1 MB partition at one end of her hard drive, so she
backed up the G: partition, ran FDISK and removed that logical drive and made
G: and H:. This did not interfere with the other partitions, so she did not
have to backup the entire system, just the one partition at the end of the hard
drive.

FDISK allows 4 entries. An entry is defined as a primary partition (boot
manager is one) or a run of logical drives. In both examples there are 3 FDISK
entries. You can have multiple primary partitions, but you can only access the
selected primary partition when booted. When booting a system that has multiple
primary partitions, think of it as choosing which one you would like to access
as C: The other primary partitions cannot be accessed.

The decision on partitioning your system must be based on your anticipated use.
The OS/2 boot manager allows for many possibilities. The partition size and
expected use will also influence your file system selection.


ΓòÉΓòÉΓòÉ 7.3. File System Selection ΓòÉΓòÉΓòÉ

To know which file system to choose, it is first necessary to understand the
two file systems. While both file systems work on the same hard drives and
partitions, there are performance reasons for choosing one over the other.

The file systems supported under OS/2 are FAT and HPFS. They are functionally
equivalent to the earlier releases. The file systems in OS/2 versions 2.0 and
2.1 support the same file sizes and partition sizes.


  Figure 3. File System Partition and File Size Support


              Max File Size       Max Partition Size

  FAT            2 GB                  2 GB

  HPFS           2 GB                 64 GB

Both HPFS and the FAT file systems have disk caching, lazy writing and
read-ahead. See ]File SystemsΓò¬ on page 22 for more information on file systems,
caches and lazy writing.

File system caches and lazy writing parameters can be changed during or after
initial installation. The default values set by installation are good for
average systems. See ]File SystemsΓò¬ on page 22 and ]The CONFIG.SYSΓò¬ on page 27
for additional tuning information.

Generally, if a partition is less than 100 MB, the file system selected should
be FAT. FAT provides excellent performance and reserves less disk space for
managing the partition than HPFS. The High Performance File System, which was
designed for the larger disk drives, generally performs better than FAT in
partitions greater than 100 MB, especially where there are many small files, a
very large file (for example a database) or the access to the disk will
generally be random.

The FAT file system manages the partition using clusters. The cluster size
varies with the partition size because only 64 KB is used to manage the entire
partition. Larger partitions have larger clusters than smaller partitions.
Since a file or directory always takesn number of clusters, this results in a
less efficient use of DASD in large partitions (a 1 byte file will take a
cluster, even if the cluster is 8 KB).

HPFS manages all partitions at a sector granular level, regardless of the size
of the partition. This allows for better use of DASD. (a 1 byte file will take
1 sector (generally 512 bytes) for data and 1 sector to manage the file (Fnode)
).

The way that the file systems manage disk space may influence your partition
size or your file system selection. Large disks formatted FAT can have cluster
sizes up to 64 sectors (generally 64 KB) resulting in poor use of your disk
space. Cluster sizes change as follows:


  Figure 4. FAT Cluster Size

  Partition Size             Cluster Size

  diskettes                    1 sector
  < 16 MB                      8 sectors
  16 to 128 MB                 4 sectors
  128 to 256 MB                8 sectors
  256 to 512 MB               16 sectors
  512 to 1024 MB              32 sectors
  1024 to 2048 MB             64 sectors

File system selection, cache sizes and options influence the performance of
application load times and run time within I/O intensive applications. See File
Systems for specific file system tuning that can be done after installation.


ΓòÉΓòÉΓòÉ 7.4. Default File System Cache Sizes ΓòÉΓòÉΓòÉ

Although the installation defaults might not be specifically customized to a
particular system, these values are easiest tuned after installation. The
default values are shown in Figure 12 on page 27. If only  the FAT file system
is installed, the default sizes are for the DISKCACHE= statement in the
CONFIG.SYS file. If the system has partitions that are all  HPFS, the default
size is for the IFS=HPFS statement in the CONFIG.SYS file. (On HPFS only
systems, the FAT diskcache is set at 64 KB) If the system uses both file
systems types, then OS/2 2.0 installation changes the cache size for both file
systems. The file system with the largest total amount of DASD (sum of the
partitions) gets the first value, the other file system gets the second value.
See File Systems for additional information.


ΓòÉΓòÉΓòÉ 7.5. Formatting the Partition ΓòÉΓòÉΓòÉ

The next decision to make at installation is whether or not to format. It is
always advisable to format the partition at installation time. This allows
clean up of any unnecessary files. It is important to remember that if you have
applications or data on that partition that it must be backed up prior to
formatting to be saved. If you select to not format the partition, installation
will continue and will clean up system files (i.e. remove WIN-OS/2 support from
2.0 at install of 2.1, replacing it with the enhanced WIN-OS/2 support)


ΓòÉΓòÉΓòÉ 7.6. Install Features Selection ΓòÉΓòÉΓòÉ

The next decision to make is which installation path to take. The Install
Preselected Features selection installs most, but not all, OS/2 features. It
takes about 27 MB of disk space (plus the swap file). Any features not
installed can be installed at a later time using the Selective Install feature.
This is the Selective Install icon located in the OS/2 System folder. Install
All Features will install all features available in OS/2. There are few
selections to be made during this install, and it takes about 35 MB of disk
space (plus the swap file). Select Features and Install requires selecting
items from several menus. This option allows you to do a custom install of your
system. The range of disk space required is 17 MB to 35 MB (plus swap file).
The lower value provides for only the minimum files required to install and run
OS/2. Figure 5 lists the features that are selectable. The minimum value refers
to having selected NO features.

Selection of features depends on personal preference. There are no performance
impacts from selecting required function. Do not install features that your
hardware cannot support (i.e. CD-ROM, PCMCIA, APM). Disk space requirements are
listed to help you understand disk space requirements only.


ΓòÉΓòÉΓòÉ 7.6.1. Preselected Install ΓòÉΓòÉΓòÉ

Preselected installation provides a general installation of OS/2 features for
users. This default is good for new users that do not have enough space for a
full install. The features provided when the pre-selected installation is taken
include all required files for OS/2 and the following features:


  Figure 5. Features Installed with PreSelected Install

  Documentation (.8MB)                 OS/2 Tutorial (168KB)


  Fonts (1.9MB)                        Helvetica (233KB)
                                       Courier (outline) (502K)

  Optional System Utilities (1.6MB)    Backup Hard Disk (29KB)
                                       Change File Attributes (37KB)
                                       Manage Partitions (228KB)
                                       Restore Backed Up Files (30KB)
                                       Sort Filter (32KB)
                                       Installation Utilities (501KB)

  Tools and Games (6.0MB)              Search and Scan Tool (71KB)
                                       Personal Productivity (1407KB)

  OS/2 DOS Support (1.3MB)             DPMI (22KB)
                                       Virtual EMS (19KB)
                                       Virtual XMS Support (8KB)

  Windows Support (9.0MB)              Readme Files (143KB)
                                       Accessories (1154KB)
                                       Screen Savers (77KB)
                                       Sound (253KB)

  High Performance File System (0.4MB)


ΓòÉΓòÉΓòÉ 7.6.2. Full Install ΓòÉΓòÉΓòÉ

Full installation option installs all features of OS/2. This selection requires
about 40 MB of disk space. Additional space is required for the swap file in
constrained systems. If your partition is small ( < 50 MB) it is advisable to
move the swap file to another partition.

The features provided when the full installation is taken include all required
files for OS/2 and ALL the features listed in selectable install.


ΓòÉΓòÉΓòÉ 7.6.3. Selectable Install ΓòÉΓòÉΓòÉ

Selectable install allows for full end-user control of features to be installed
on a system. There are several options available on menus, and sub-menus allow
for a more specific selection. For example, you can choose to select (or not
select) all the productivity aids, or you can use the sub-menu to select some
of the productivity aids.

The selectable install is the best selection for users who understand the
features available, and for users that are concerned with disk requirements.
The 2.1 release is larger (especially the enhanced WIN-OS/2 support) and
selectable install will provide you with a full range of feature selection.
Remember that the more features selected the more disk space required. Also,
the more entries in a folder, the slower the performance when opening that
folder. For example, if you select all the productivity aids and games, then
opening the productivity folder will be slower than if you had only the 2
productivity aids you actually used. All features can be added after
installation by using selective install in the system setup folder. (For
deleting features, see Removing Features

When selecting features, include REXX support if you will be installing OS/2
Lan Services or OS/2 Communication Services. Rexx is required to successfully
run those programs.


  Figure 6 (Page 1 of 2). Selectable Features

  Documentation (.8MB)       OS/2 Tutorial (168KB)
                             OS/2 Command Reference (391KB)
                             REXX Information (195KB)

  Fonts (1.9MB)              Courier (92KB)
                             Helvetica (233KB)
                             System Mono-spaced (35KB)

                             Times Roman (215KB)
                             Courier (outline) (502KB)
                             Helvetica (outline) (395KB)
                             Times New Roman (outline) (430KB)

  Optional System Utilities  Backup Hard Disk (29KB)
  (1.6MB)                    Change File Attributes (37KB)
                             Display Directory Tree (34KB)
                             Manage Partitions (228KB)
                             Label Diskettes (34KB)
                             Link Object Modules (472KB)
                             Picture Viewer (33KB)
                             PM REXX (85KB)
                             Recover Files (47KB)
                             Restore Backed Up Files (30KB)
                             Sort Filter (32KB)
                             Installation Utilities (501KB)

  Tools and Games (6.0MB)    Enhanced Editor (926KB)
                             Search and Scan Tool (71KB)
                             Terminal Emulator (1592KB)
                             PM Chart (1201KB)
                             Personal Productivity (1407KB)
                             Solitaire - Klondike (388KB)
                             Reversi (34KB)
                             Scramble (62KB)
                             Cat and Mouse (53KB)
                             Pulse (40KB)
                             Jigsaw (71KB)
                             Chess (266KB)

  OS/2 DOS Support (1.3MB)   DOS Protect Mode Interface (22KB)
                             Virtual EMS (19KB)
                             Virtual XMS (8KB)

  Windows Support (9.0MB)    Readme Files (143KB)
                             Accessories (1154KB)
                             Screen Savers (77KB)
                             Sound (256KB)

  High Performance File System (.4MB)

  Advanced Power Management (.1MB)

  PCMCIA Support (.1MB)

  REXX (.4MB)

  Serviceability and Diagnostic Aids (.7MB)

  Optional Bit-maps (.1MB)


ΓòÉΓòÉΓòÉ 7.6.4. System Configuration Menu ΓòÉΓòÉΓòÉ

After  you select which installation path, and  before  you select features in
a preselected install, the System Configuration Menu is displayed. Usually, the
correct hardware support is shown here. There are some exceptions on non-IBM
hardware, so check this screen carefully to verify that install recognized all
your hardware. At this time, any of these items can be changed. The following
figure shows which items can be changed from the System Configuration Menu.


  Figure 7. Installation- System Configuration Menu

  System                     Mouse
                             SerialDevice Support
                             Primary Display
                             Secondary Display

  Locale                     Country
                             Keyboard

  Peripherals                CD_ROM Device Support
                             SCSI Adapter Support
                             Printer


ΓòÉΓòÉΓòÉ 7.6.5. Display  Selection ΓòÉΓòÉΓòÉ

The System Configuration Menu allows you to select the display driver based on
your hardware. You can choose installing VGA on SVGA, 8514 or XGA systems. High
resolution display drivers must handle a greater number of points on the screen
(called pixels) and the performance will be somewhat slower. However, the
advanced hardware has improved performance so the overall result is:

o The best performance with excellent resolution will be with XGA display
  drivers
o Low resolution and good performance with the VGA display driver,
o Excellent resolution and moderate performance with SVGA display drivers.

The PM XGA display driver will only work on XGA hardware (display adapter and
display) and the PM SVGA display driver will only work on SVGA hardware
(display adapter and display). Similarly, the PM 8514 display driver will only
work with the 8514A display adapter card and appropriate display.

The type of hardware display of the system will be shown under "Primary
Display" on "System Configuration" panel. If it is not correct,or you wish to
change it, you may click on "Primary Display", "O.K.", and choose the correct
display accordingly. The supported resolutions for each display are illustrated
in Figure 8.


  Figure 8. OS/2 2.1 Display Driver Resolutions

  Resolutions    640x400         640x480         800x600    1024x768

  Colors       256  65,536   16   256  65,536      256       16  256

  VGA                        X

  XGA           X     X            X      X                   X    X

  SVGA                             X                 X             X

  IBM 256c                         X

  8514                                                             X

In addition to the displays described in the following subsections, OS/2 2.1
also supports EGA and CGA. Because of the highly graphical user interface
provided by the Workplace Shell, use of OS/2 2.1 in these modes will be
difficult and is not recommended.

o VGA

  The only resolution for VGA is 640 x 480 x 16 colors. All XGA and SVGA
  display adapters are also supported in VGA mode with the VGA driver shipped
  with OS/2 2.1.

o XGA

  The default resolution during installation depends on the amount of available
  VRAM on the system. This is the same for XGA and XGA-2 display adapters. For
  systems with 0.5 MB VRAM, the default resolution is 1024 x 768 x 16 colors
  while for systems with 1.0 MB VRAM, the default resolution is 1024 x 768 x
  256 colors. It requires 1.0 MB VRAM to run in 1024 x 768 x 256, 640 x 480 x
  64K and 640 x 400 x 64K color modes. You can change the resolution and colors
  to be displayed on the screen after initial installation. See Changing
  Display Drivers for additional information.

  The XGA display drivers support both the XGA and the XGA-2 adapter cards.
  Addi- tionally, the new XGA-2 display subsystem has a built-in utility called
  Display Mode Query Set (DMQS), which can take care of setting up optimum
  parameters for given display devices. The correct selection of display type
  is automatically done by OS/2 2.1 installation program. It can be changed
  after installation. See Changing Display Drivers for information on changing
  and tuning display drivers.

o SVGA

  The implementation of SVGA varies widely and requires different device
  drivers for different resolutions, as well as different adapters and systems.
  OS/2 2.1 supports the following SVGA chip sets:

   - ATI Technologies Inc., ATI28800

   - Headland Technology Inc.,Chip Type: HT209.

   - Trident Microsystems, Chip Type: TVGA 8900B and TVGA 8900C.

   - Tseng Laboratories, Chip Type: ET4000.

   - Western Digital Corporation, Chip Type: WD90C11, WD90C30, and WD90C31 (in
     C30 compatibility mode).

   - Cirrus Logic Inc., Chip Type: CL-GD5422 and GD5424

   - IBM Corp., Chip Type: IBM VGA 256c and SVGA-NI.

  The default driver during installation is VGA driver (640 x 480 x 16 colors),
  if your SVGA hardware is not detected by install. The resolution may be
  changed by installing the drivers for the desired resolution. See Changing
  Display Drivers for additional information.

  At least 0.5 MB VRAM is needed to install the SVGA drivers. At 0.5 MB VRAM,
  only the OS/2 SVGA resolution of 640 x 480 x 256 colors is supported. Both
  the 1024 x 768 x 256 colors and 800 X 600 X 256 colors resolutions require 1
  MB VRAM.

o 8514

  The only resolution available for 8514/A display is 1024 x 768 x 256 colors.
  The driver is the new 32-bit driver.

o Seamless Support (WIN-OS/2)

  WIN-OS/2 display drivers are automatically copied at installation time for
  the display type selected. WIN-OS/2 support for executing Windows
  applications is provided in full screen or seamless (windowed) sessions.
  Seamless support is provided in the display device driver, and that support
  has changed between releases. In version 2.0, only the VGA display driver
  provided seamless support. All other display drivers supported WIN-OS/2 in
  full screen only. In version 2.1, VGA, XGA and SVGA display drivers shipped
  with OS/2 support seamless execution for WIN-OS/2. Additional display drivers
  having support for seamless execution of WIN-OS/2 may be available after OS/2
  2.1 ships.


ΓòÉΓòÉΓòÉ 7.6.6. The OS/2 Setup and Installation Menu ΓòÉΓòÉΓòÉ

The OS/2 Setup and Installation menu, seen in selective install only, allows
you to select which features to install. Sub-menus provide flexibility in
choosing the features. These selections generally provide function only, and
the disk space window lets you know the disk space available and the disk space
needed for the items you have selected. Font support selection can affect
performance and memory. More information is provided here to help in the
selection process.


ΓòÉΓòÉΓòÉ 7.6.7. Font  Support ΓòÉΓòÉΓòÉ

During the selective install process, you can select which of the fonts shipped
with OS/2 should be installed in your system. See Figure 9 for a list of the
fonts supplied by OS/2.


  Figure 9. OS/2 Supplied Fonts

  Courier
  Helvetica
  System-Mono Spaced
  Times-Roman
  Courier Outline
  Helvetica Outline
  Times New Roman Outline

You should only install those fonts that you will actually use on your system.
This will not only save you disk space, but will also improve your performance
when loading applications that use fonts, and reduce the amount of system
resources being used. Each font that is installed in the system will use a
minimum of 2 KB of memory even if it is not being accessed. This number will
increase significantly when you actually start to use the font in an
application.

Outline fonts tend to be more efficient from a performance point of view since
only the characters that are actually used are cached into memory. With
non-outline (bit-mapped) fonts, the entire bit-map character rendering buffer
is loaded into memory. This can increase the working set and cause the system
to enter into a paging situation. Also, bit-mapped fonts are defined for a
specific screen resolution and device. Outline fonts are scalable and loaded
for the specific device installed on your system. Outline fonts can also be
downloaded to certain printers and increase performance.

Additional fonts can be added after the installation process. Selecting only
the outline fonts reduces disk space requirements and keeps system performance
optimal.


ΓòÉΓòÉΓòÉ 7.6.8. Software Configuration Menu ΓòÉΓòÉΓòÉ

The Software Configuration  pull down menu allows you to change OS/2 Parameters
and DOS Parameters. Tuning information on these items is provided in the system
tuning section (These changes can be made during or after installation). Page
numbers where the information can be found are provided for ease of use during
install. Figure 10 shows the items that can be changed from the Software
Configuration Menu.


  Figure 10. Software Configuration Menu

  Software Configuration

              OS/2 Parameters        Printer Monitor Buffer Size
                                     Buffers
                                     Diskcache
                                     Maxwait
                                     Swap Minfree
                                     Threads
                                     Swappath
                                     Memman Protect
                                     Memman Swap
                                     Priority

              DOS Parameters         Break
                                     Open FCBS
                                     Protected FCBS
                                     RMSize

Swap  File

The swap file (SWAPPER.DAT) default placement is on the installed partition in
\OS2\SYSTEM. If you are running tight on disk space, move this file to another
partition. The swap file is moved to another partition at installation time
from the software configuration menu (see above). The swap file can be moved
after installation by changing the SWAPPATH= line in the CONFIG.SYS. These
changes take effect at the next boot. More information on the swap file is
included in the file system section, including the parameters and swap file
placement.


ΓòÉΓòÉΓòÉ 7.7. Migrating Applications ΓòÉΓòÉΓòÉ

The Migrate Applications utility can be run during the install process or from
the System Setup Folder. It uses a migration database to define what specific
changes need to be made to DOS and WIN-OS/2 session settings, as well as how
OS/2, DOS and Windows applications should be setup. This database is called
DATABASE.DAT and is located in the \OS2\INSTALL subdirectory of your OS/2
system. A text version of this file, called DATABASE.TXT, also exists in the
\OS2\INSTALL subdirectory to allow you to change the settings of a particular
application, or to add new applications to the database.

Migrate should be used, either at install time or after an application is
installed, to setup the application and place its icon in the appropriate
folder. The customized settings for applications listed in the migration
database are good general defaults. After installation, see the sections on
tuning applications for additional changes to improve performance.


ΓòÉΓòÉΓòÉ 7.8. Installation and WIN-OS/2 Support ΓòÉΓòÉΓòÉ

When installing OS/2 2.1 over a prior version of OS/2 2.x, the WIN-OS/2 support
previously provided will be deleted. This is true even if you installed using
the WIN-OS/2 beta and placed WIN-OS/2 on another partition. You may defer the
installation of WIN-OS/2 3.1 by not selecting WIN-OS/2 3.1 installation during
the installation phase. However, install will remove WIN-OS/2 3.0 regardless of
whether WIN-OS/2 3.1 is installed or not.

If you decide to install WIN-OS/2 3.1, you will have an option to either
install a new Windows desktop or preserve the current desktop. Select this
option if you would like to keep the customized Windows desktop you already
have installed. You will also have the option to install to a partition other
than the one where you are installing OS/2. This provides flexibility on
systems where the install partition is too small for all the features selected.


ΓòÉΓòÉΓòÉ 8. What Else Can be Changed to Improve Performance? ΓòÉΓòÉΓòÉ

After installation, there are additional changes that can be made to improve
the performance of OS/2. Some of these items are general in nature and apply to
the overall system performance. Some changes are specific for certain systems
or certain applications. These changes are included in this section.


ΓòÉΓòÉΓòÉ 8.1. General System Changes ΓòÉΓòÉΓòÉ

There are some changes that affect the performance of the entire system. They
are included here with information on their system impact so that you may tune
your system as needed.


ΓòÉΓòÉΓòÉ 8.1.1. Animation ΓòÉΓòÉΓòÉ

On memory constrained, low end systems, the performance when opening folders
and starting sessions can be improved by disabling animation. Animation is the
process of drawing boxes on the screen that appear to grow in size culminating
in an open folder or session. This gives a nice appearance when systems are
performing well. If you are running on a 80386 SX system and are overcommitted
in memory, performance is improved if animation is disabled.

To disable desktop animation, open the System Setup icon in the OS/2 System
folder. Select the System icon, and go to the page with the Window bookmark.
This screen allows you to select Disable Animation.


ΓòÉΓòÉΓòÉ 8.1.2. Changing Display Drivers ΓòÉΓòÉΓòÉ

You may decide to change display drivers on your system. The different display
drivers affect the performance of your system. Resolutions on the XGA and SVGA
systems also affect performance. The section ]Display SelectionΓò¬ on page 13
describes the various display drivers that are available with their resolutions
and number of colors supported. The following information details how to change
the resolution.

 1. Select "OS/2 System".
 2. Select "System Setup".
 3. Select "System".
 4. Choose the new display type
 5. Choose the desired resolution
 6. Follow remaining selections
 7. Shutdown and reboot the system.

Note: If you are changing from one type of SVGA hardware to another type, it is
best if you change the display driver to VGA before you change hardware, then
change back again to the correct display driver type. This will keep you from
having a display driver / hardware mismatch that could necessitate reinstalling
OS/2.

The following information details how to change the display driver.

 1. Select "OS/2 System".
 2. Select "System Setup".
 3. Select "Selective Install".
 4. Click on Primary Display
 5. Click OK
 6. Choose the desired display type
 7. Follow remaining selections
 8. Shutdown and reboot the system.


ΓòÉΓòÉΓòÉ 8.1.3. Minimize Applications and Folders ΓòÉΓòÉΓòÉ

When working with OS/2, you will have better system responsiveness if you
minimize applications between uses. Performance when accessing a minimized
application is faster than starting the same application. This is also true
when working with folders. When you have applications or folders that you use
often, leaving them open at shutdown (or placing them in the startup folder)
will cause them to be loaded at system boot time, and accessing them will be
significantly faster.


ΓòÉΓòÉΓòÉ 8.1.4. Starting Applications ΓòÉΓòÉΓòÉ

Performance when starting applications may not be as quick as you would like.
This is espe- cially true if your system is memory constrained or has slow
DASD. Some steps can be taken to reduce the application load time.

Start applications from their own subdirectory, or call the application with a
fully qualified path. This will reduce the search time for OS/2 to locate the
file(s). Using the icon to start the application is optimal. The icon will have
(if migrated or correctly installed) the exact path for executable and data
files. Be certain that the PATH, LIBPATH and DPATH statements in the CONFIG.SYS
are arranged with the most frequently accessed subdirectories listed first.
Also, start the application earlier by leaving it open at shutdown, or by using
the startup folder.


ΓòÉΓòÉΓòÉ 8.1.5. Use Startup Folder ΓòÉΓòÉΓòÉ

Applications and folders can be opened several ways. If they were left open at
shutdown, they will reopen at boot time after the Workplace Shell is started.
Applications placed in a STARTUP.CMD file will also be processed at boot time,
after the Workplace Shell is started. Applications and folders placed in the
Startup Folder will be opened with the processing overlapping the startup of
the Workplace Shell. This use of the Startup Folder is preferred because it
takes advantage of OS/2 multitasking.


ΓòÉΓòÉΓòÉ 8.1.6. Multitasking Considerations ΓòÉΓòÉΓòÉ

OS/2 is a true multitasking operating system. It manages multiple processes
concurrently by sharing the system CPU (called timeslicing). If your system has
enough processing power, you will not see any performance degredation when
executing multiple applications. However, if your system is memory
overcommitted or if you are constrained by the processer you may experience
performance problems. There are several steps you can take to improve
performance.

First you should verify that you are only running programs that are necessary.
If you have any processes that are not needed (for example Pulse, Cat and
Mouse, a clock, etc.) they should be closed. Those applications, when running,
take cycles from the processor. This would affect the performance of other
applications that are executing. If you have a problem with foreground tasks,
they may be affected by background applications. Verify that the settings are
correct for the application, especially DOS applications that may poll, so that
useful tasks are always processing. On memory constrained and 80386SX systems,
you should limit background processing to improve foreground performance. This
would not mean that you should close background applications, but you will have
better response time in your active application if the other applications are
not concurrently processing.

This also applies if you are running memory and file I/O intensive applications
concurrently (for example printing from an application, reflowing a large
document, processing a large data base, etc.). While OS/2 allows you to run
many applications at once, this can cause a problem is some systems when the
processer or memory become overcommitted. Also see Does the Hardware Impact
Performance on OS/2 ? for information on hardware upgrades.


ΓòÉΓòÉΓòÉ 8.2. Swap File Tuning ΓòÉΓòÉΓòÉ

Current hardware allows operating systems to assign virtual address space to
applications. This address space can be backed by either real memory or by disk
space. When more memory is needed to execute programs than is currently
available in the system, OS/2 moves some of the information stored in memory
off to the hard drive. This is called swapping or paging. In OS/2, the file
where the data is written is the SWAPPER.DAT file.

The swap file parameters have changed from the prior releases. This was due to
functional changes but also provides for easier tuning for increased
performance. The swap file is used for paging in overcommitted systems and to
store some data not being accessed frequently. It is allocated at boot time,
reducing fragmentation.

There are two parameters -- the first value is the  MinFree Value , the second
is the Initial Swap File Size . Both are expressed in KB, and the system rounds
them to megabytes at boot time. The MinFree Value determines at what time you
will receive a warning message that disk space has been reduced too low. When
the swap file grows, the system checks for the remaining disk on the partition
where the swap file is located. If the remaining amount of free space, after
the swap file extension, is less than the amount (in megabytes) of the minfree
value, a message is displayed. This should be set to provide you time to take
action so that additional swap file extensions are not halted due to lack of
disk space.

The options available when the warning occurs are:

o End Program/Command/Operation
o Ignore the Error and Continue
o Display Help

If you choose to ignore the warning, and the system tries to extend the swap
file without having disk space to handle the request, the system will halt --
no additional warnings, no chance to save data.

If you let the system end the program that requested the memory, it will
probably end the appli- cation that is just loading OR the workplace shell.
(The workplace shell places many requests for memory on the system. It will
restart after the system ends it) The best solution is for you to take the time
to exit applications that you are no longer being used, since you are most
knowledgeable on what is or will be needed. In any case DO NOT IGNORE THE
MESSAGE.

The best minfree value for your system is generally 4096 for systems running
average applications. If a system will be dealing with large databases or large
spread sheets or text files, increase the value to 6144 or larger. This will
give you an earlier warning for a shortage of DASD space for the SWAPPER.DAT
file.

The initial swap file size is preallocated to a minimum size during system
boot-up, depending on the amount of physical memory installed in the system.
This helps prevent the excessive overhead of growing the swap file
incrementally during paging operations. The user should change the preallocated
size of the swap file using the SWAPPATH directive in the CONFIG.SYS file.

While the system is running, more swap file space is needed than what has
already been preallo- cated, the kernel will to grow the swap file in 1 MB
increments. The swap file will be grown only during the processing of page
faults, when it is determined that more swap space is needed. When one or more
pages need to be swapped out from memory, the kernel will determine if these
pages already have swap space allocated in the swap file. If so, the swap
manager will simply write them into the allocated swap space. Otherwise, new
swap space will be allocated in the swap file. If there is no space left, the
swap file will be grown. The swap manager then writes the pages to their new
swap space. Swap space in the swap file is normally not freed up until the
corresponding memory is deallocated. When the swap file grows beyond the
initial size, then the system must manage the swap file to determine when
compaction can take place. This additional overhead will cause a performance
penalty. To keep your system performance optimal, make sure the initial swap
file size is correct.

To determine the correct size for your swap file, use your system as you
usually would, occa- sionally checking the size of the SWAPPER.DAT file. The
size specified in the CONFIG.SYS should be at least this size, 1 or 2 MB
larger, DASD permitting.

The swap file contents include both code and data. The information stored there
is either backing in overcommitted systems (you are running programs whose
working set is larger than real memory on your system) or 16-bit OS/2
application code and resources. It is probably a combination of both. The
reason the 16-bit OS/2 application code and resources are backed in the swap
file is to improve performance by reducing working set. Segmented 16-bit
applications require the entire segment to be brought into system memory, even
if you only need a piece (page) of that segment. This would mean that
application code segments would be completely loaded whenever references were
made to discarded pages. (OS/2 will discard pages not referenced by aging,
least referenced page discarded first) When OS/2 initially loads a 16-bit OS/2
application, it packs the segments into pages and copies them to the swap file
for faster recovery when needed. This can be disabled by using the NOPACK
option on the MEMMAN= line in the CONFIG.SYS. However, the performance decrease
and larger working set will rarely offset the potential of a reduced swap file
size.

The swap file shrinks when several conditions are met. When the amount of free
swap space in the swap file exceeds 1.5MB, swap file compaction will be
performed at system idle time. During compaction, free swap space will be moved
to the end of the swap file. After compaction, when the amount of free space at
the end of the swap file is greater than 1 MB, the swap file will be decreased,
in 1MB increments. The swap file only compacts when it has grown larger than
the size initially set in the CONFIG.SYS. Growing and shrinking of the swap
file is always managed in 1MB increments.


ΓòÉΓòÉΓòÉ 8.3. File Systems ΓòÉΓòÉΓòÉ

The file systems supported under OS/2 are FAT and HPFS. They are functionally
equivalent to the earlier releases. Both HPFS and the FAT file systems have
disk caching, lazy writing and read-ahead.

Disk caching is the placing of frequently accessed data in a special buffering
storage. It reduces access time and improves the performance of applications
that rely heavily on hard disk data.

Lazy writing (or write behind) is the writing to disk file updates when the
operating system is idle, when the updated (dirty) cache block is aged, or when
the cache is full of updated (dirty) cache blocks. Cache blocks are aged by a
set of parameters described in detail later in this section.

Read-ahead is when the file system detects sequential read requests in a file
and extends the read (reads ahead), placing that data in the file system cache
to improve performance. Read-ahead is an internal function of the file system,
and not settable by the end user.

To minimize the frequency with which the system ties up its resources writing
cached data to the disk, both file systems also can take advantage of the
lazy-writing  feature. Lazy writing provides a significant performance
improvement when writing to the disk.

To allow the operating system the greatest chance for finding data in the
cache, both file systems incorporate asynchronous read ahead for sequential
I/O. This read-ahead capability is always enabled in OS/2 2.0.

For applications that require absolute data integrity, files should be opened
with WriteThru enabled. WriteThru ensures that disk write operations are
committed to disk before the application continues. This is in direct contrast
to lazy writing; lazy-written data can remain in the file-system cache for
several seconds after the application has completed writing. Disabling the
lazy-writing feature of either file system does not provide the same capability
as enabling WriteThru, and it decreases system performance. When it is not
possible to open a file with WriteThru enabled, the shutdown procedure must be
used to ensure that all data is written to disk.

The lazy writing parameters for both file systems will cause updates in the
cache to be written to disk when the disk is idle or when the update is 5
seconds old. It takes the operating system only a second or two to complete the
updates to disk. The parameters cause writes to the disk when the cache is
approximately 30% full of dirty blocks (updates). This means that the actual
window of 'lost' data in the case of a power interruption is small -- at
maximum, the last 7 seconds of updates, to around 50% of the total cache size.

Shutdown flushes all system buffers guaranteeing that file system updates in
the cache are written to disk before power off or reboot. CTRL-ALT-DEL flushes
the buffers in the same way, also providing for data updates to disk at reboot
time. Using either of these functions will ensure file updates are written to
disk.

Generally, if a partition is less than 100 MB, the file system selected should
be FAT. FAT pro- vides excellent performance and reserves less disk space for
managing the partition than HPFS. The High Performance File System, which was
designed for the larger disk drives, generally per- forms better than FAT in
partitions greater than 100MB, especially where there are many small files, a
very large file (for example a database) or the access to the disk will
generally be random.


ΓòÉΓòÉΓòÉ 8.3.1. FAT File System ΓòÉΓòÉΓòÉ

The FAT file system contains no significant changes from OS/2 version 2.0.

The FAT file system contains the following enhancements in 2.0 that provide
improved perform- ance and enhanced support for disk hardware devices:

o Command chaining by attempting to call the volume manager with a list of all
  contiguous sector requests required to fill an I/O request, thereby enabling
  multiple I/O requests in a single logical operation.

o Scatter and gather by passing physical pointers to each page in the data
  buffer (physically discontiguous) as part of the I/O request. This allows I/O
  controllers, such as the IBM SCSI adapters, that support the scatter and
  gather capability to perform the I/O in a single operation.

o Disk caching within the FAT file system, rather than in the device driver.

o Recognition of devices that have onboard caches (nonsystem memory),
  incorporating them into the total caching scheme.

o Faster allocation of free space on the logical drive, using a bit map to
  track free clusters on the disk.

  FAT supports Extended Attributes to a maximum of 64KB per file or directory.

The FAT file system manages the partition using clusters. The cluster size
varies with the parti- tion size because only 64 KB is used to manage the
entire partition. Larger partitions have larger clusters than smaller
partitions. Since a file or directory always takesn number of clusters, this
results in a less efficient use of DASD in large partitions (a 1 byte file will
take a cluster, even if the cluster is 8 KB). See Figure 4 on page 9 for
cluster size information.


ΓòÉΓòÉΓòÉ 8.3.2. High Performance File System ΓòÉΓòÉΓòÉ

The High Performance File System has made some internal changes to improve
performance. In version 2.1, when small files (1/8th the cache size; max file
size 128 KB) are opened, they are immediately read into the HPFS cache. This
allows for increased performance when accessing the data in that file.

The HPFS under OS/2 supports the following:

o Command chaining by calling the volume manager with a list of all contiguous
  sector requests required to fulfill an I/O request. This function is
  supported for all DASD types.

o Scatter and gather by passing physical pointers to each page in the data
  buffer (physically discontiguous) as part of the I/O request. This enables
  I/O controllers, such as the busmastering IBM SCSI adapters, that support the
  scatter and gather capability to perform the I/O in a single operation.

o Disk caching in the IFS driver, rather than in the device driver.

o Recognition of devices that have onboard caches (non-system memory),
  incorporating them into the total caching scheme.

HPFS manages all partitions at a sector granular level, regardless of the size
of the partition. This allows for better use of DASD. (a 1 byte file will take
a sector, generally 512 bytes).

HPFS supports Extended Attributes to a maximum of 64 KB per file or directory.
HPFS will perform best when the number of files in a directory are kept below
5,000.

Note: File system selection, cache sizes and options influence the performance
of application load times and run time within I/O intensive applications. File
system performance will generally not affect the performance of CPU bound
programs or user interactive applications. Your application is I/O intensive if
there are many I/O requests (hard drive access light stays lit). File system
performance will also affect the load times of large applications and
applications where large files are loaded and saved (desktop publishing &
applications using large files (spread sheets) are examples).


ΓòÉΓòÉΓòÉ 8.3.3. Partition Size and File System Performance ΓòÉΓòÉΓòÉ

The FAT file system is basically the traditional DOS file system with some
enhancements in the file system cache and lazy writing (write-behind)
available. The High Performance File System, first available in OS/2 1.2, was
designed to handle large DASD and large files. HPFS uses B-trees to locate the
information on directories and files. Both file systems perform well on small
(<100 MB) partitions. The advantage goes to HPFS in large (>100 MB) partitions
because of the faster access through the B-tree. B-tree searching allows faster
access to HPFS also manages DASD space at a sector granular level rather than
by clusters like FAT.

What this means is that if a system has a small hard file, or is partitioned
into small (< 100 MB) partitions, the file systems perform generally the same.
The FAT file system is preferable because it uses less disk space to manage the
files and directories. The FAT file system is always active in OS/2 (HPFS does
not handle diskettes). HPFS is started by the statement:

IFS=C:\OS2\SYSTEM\HPFS.IFS /c:64

in the CONFIG.SYS. If a system does not need HPFS, removing this line reduces
memory requirements by 100 KB when not accessed, and approximately 500 KB when
accessed. If memory is constrained, this will help improve overall system
performance. If the system is not overcommitted, removal of this option will
not improve performance. If any partition size is large ( >100 MB ), HPFS
should be used for function as well as performance.

Special consideration should be given if you will be installing Windows
applications. Many of these applications place files in the WINDOWS\SYSTEM
subdirectory. This forces you to plan ahead for disk space requirements to
install these applications. Additional consideration must also be given if an
you expect to boot and execute under native DOS. Native DOS (all versions) does
not provide access to HPFS formatted partitions.


ΓòÉΓòÉΓòÉ 8.3.4. File System Caches and Lazy Writing ΓòÉΓòÉΓòÉ

Whether a system is using FAT, HPFS or both, tuning the file system cache has
performance advantages for heavy I/O applications. Both file systems allow
various cache sizes as well as threshold parameters. There are some functional
differences in the file systems.


  Figure 11. Cache and Lazy Writing Parameters

                             FAT                 HPFS

  Cache Size Minimum        64 KB                64 KB
             Maximum        14 MB                 2 MB

   Threshold Default         2 KB                 4 KB
             Minimum         2 KB                 2 KB
             Maximum        64 KB                64 KB

    Read Ahead Value         8 KB                 8 KB

    Cache Parameters
              MaxAge      5000 ms              5000 ms
             (range)    not settable           1 - 99999

            DiskIdle      1000 ms              1000 ms
             (range)    not settable           1 - 99999


          BufferIdle       500 ms               500 ms
             (range)    not settable           1 - 99999

  All cache parameter values are milliseconds

Cache parameters determine when data will be lazy written to disk. Consult the
OS/2 Command Reference for more information. Changes in these values generally
have no discernible impact on system performance The read ahead value is not
settable by the end user, and is provided here for information only. The
threshold value (CRECL) will affect the performance of I/O intensive
applications. This value determines the cut off point at which I/O requests are
not cached by the file system. If your application uses large I/O requests,
performance will be improved when this value is increased to include the larger
I/O size. This would mean more data will be available in the file system cache.
This is useful if the application accesses the same data repeatedly, or if the
application accesses the data sequentially. This value does have a dependency
on the file system cache. The file systems will not allow I/O requests greater
than 1/4 of the total cache into the file system cache. This is to prevent
constant overwriting of data in the cache. If you increase the threshold value,
be certain that the file system cache can use that value with the cache size
set. OS/2 will ignore unacceptable threshold value, and use the default value.

The file system cache is used for I/O requests that are less than the threshold
value set, or 1/4 of the cache size maximum. Increasing the cache size will
improve performance for I/O intensive applications. Experiment with various
values to determine the best setting for your application. Each file system has
its own cache. If both file systems are enabled, determine the file system that
will be used for the I/O intensive applications and increase the size of that
file system's cache. Decrease the size of the other file system cache. Decrease
both file system caches if your application is not I/O intensive, as this will
free up memory for your application(s).

EXAMPLES: These examples only suggest changes for systems, and assumes that
memory is NOT overcommitted.

CPU Application.

  System Setup - C: is the system partition, 60MB, FAT
  D: is the application partition, 100MB, HPFS
  Application - Desktop Publisher & Graphical Application

  Decrease the size of the file system caches. 64K for FAT and
  128K for HPFS will probably be sufficient.
  No changes in threshold.

DASD Application.

  System Setup - C: is the system partition, 60MB, FAT
  D: is the application partition, 100MB, HPFS
  Application - Spread sheet and Database applications.

  Increase the size of the HPFS cache, threshold to 64K.
  Decrease the size of the FAT cache, no change to threshold

DASD Application

  System Setup - C: is the system partition, 70MB, FAT
  D: is the application partition, 210MB, HPFS
  Application - Large Spread sheet and/or Database applications.

  Increase the size of the HPFS cache, increase threshold to 64K.
  Decrease the size of the FAT cache, no change to threshold

CPU Application

  System Setup - C: is the system partition, 60MB, FAT
  D: is the application partition, 60MB, FAT
  Application - Desktop Publisher & Graphical Application


  REM out the IFS line for HPFS. Decrease the FAT cache.
  No change in FAT threshold.


ΓòÉΓòÉΓòÉ 8.3.5. Default File System Cache Sizes ΓòÉΓòÉΓòÉ

Although the installation defaults might not be specifically customized to a
particular system, it is beneficial to have access to larger cache sizes.
Therefore, OS/2 2.x installs with larger cache sizes when additional memory is
available on the system. system.

The default values are shown in Figure 12 on page 27. If only the FAT file
system is installed, the default sizes are for the DISKCACHE= statement in the
CONFIG.SYS file. If the system has partitions that are all  HPFS, the default
size is for the IFS=HPFS statement in the CONFIG.SYS file. If the system uses
both file systems types, then OS/2 2.x installation changes the cache size for
both file systems. The file system with the largest total amount of DASD (sum
of the partitions) gets that larger value (listed under 2 file systems) and the
other file system gets the smaller value. See the section on File Systems for
additional information.


  Figure 12. Installed Cache Default Sizes


  Memory Size in MB     One File System     Two File Systems

         4                   128                128 / 64

         5                   128                128 / 64

         6                   256                256 / 64

         7                   256                256 / 128

         8                   512                256 / 256

         9                   512                256 / 256

   10 through 16             1024               512 / 512

   17 through 32             2048              1024 / 1024


ΓòÉΓòÉΓòÉ 8.4. The CONFIG.SYS ΓòÉΓòÉΓòÉ

OS/2 provides many options and tunable settings. The default settings are
designed for the 'average' user. Certain assumptions were made that will not
apply to all end users. While these choices are excellent for general use, some
changes can provide for increased performance in the end user environment. The
following is intended to provide information to allow you to change the
settings to tune the system for your specific requirements.


ΓòÉΓòÉΓòÉ 8.4.1. Customizing ΓòÉΓòÉΓòÉ

There is a considerable amount of flexibility in the settings in the
CONFIG.SYS. Generally end users try to make changes and 'see what happens'.
This can lead to the situation where the system will not boot. Use the new
ALT-F1 feature or boot from a diskette to recover. The ALT-F1 feature takes the
CONFIG.SYS, OS2SYS.INI and OS2.INI from the install directory and replaces them
over the existing files. To use this optimally, set up your system as you like
it (Workplace Shell included) and then copy those files over to the OS2\INSTALL
subdirectory on the boot partition. This allows experimentation without high
risk -- recovery is to the last saved setup. If you don't make any changes, the
files saved are the CONFIG.SYS and INI files from initial installation.
Considerable time can be saved by copying these files after system changes are
made.

You might want to copy a CONFIG.SYS file from a network server or from a
previously installed system. However, using the statements from an existing
system for another system might not enable optimum performance of the second
system, because many of the parameters for the CONFIG.SYS statements are
dynamically determined at install time based on the configuration of the
system. See the section on Installation for more specific information.
Customizing the OS/2 2.1 CONFIG.SYS file improves performance and reduces
memory requirements. This section describes some OS/2 2.1 CONFIG.SYS
statements.

PATH=

Specifies the directories and search sequence to find .EXE, .BAT, .CMD and .COM
files. The path statement should be tuned for your particular system. By
placing the most commonly used directories in the beginning of the path,
performance can be improved. This reduces the number of directories that must
be searched to locate a particular file.

LIBPATH=

Specifies the directories and search sequence to find DLLs, resources and
fonts. Specify the most frequently accessed directories first so the operating
system can find them faster. A .; in the beginning of the LIBPATH tells OS/2 to
search the current directory first.

DPATH=

Specifies the directories and search sequence to find data. Specify the most
frequently accessed directories first so that the operating system can find
them faster.

SWAPPATH=

Specifies the location of the swap file, the minfree value, and the initial
size. See the section on the swap file for specific tuning information. The
default location for the file is \OS2\SYSTEM. Both values are given in KB. All
changes take effect after the next boot.

The following statement will create the SWAPPER.DAT file in the OS2\SYSTEM
subdirectory on the D: partition, with a minfree value of 2MB, and an initial
size of 4MB.

SWAPPATH=D:\OS2\SYSTEM 2048 4096

The following statement will create a SWAPPER.DAT file in the root directory on
the E: partition, with a minfree  value of 5MB, and an  initial size  of 12MB.

 SWAPPATH=E:\ 5120 12288

DISKCACHE=

Specifies the size (in KB) of memory to allocate for use for the FAT file
system's disk cache, whether FAT lazy writing is enabled, and the threshold (in
sectors) for caching disk reads.

Caching speeds up applications that read hard disks by keeping frequently
accessed hard disk data in a cache. However, increasing the size of the disk
cache decreases the size of available memory. See Figure 12 for the default
disk cache sizes.

If the LW parameter is specified, FAT lazy writing is on. Lazy writing is a
feature whereby actual writing of data to the hard disk is deferred. This
allows control to be returned to an application without having to wait for the
completion of I/O operations. Disabling lazy writing severely degrades system
performance.

The default enables lazy writing.

The following statement sets the FAT file system cache at 128 KB with lazy
writing enabled.

DISKCACHE=128,LW

The threshold parameter specifies the number of sectors that will be placed
into cache for read operations. If the threshold parameter is not specified (as
in the previous example), it defaults to a value of 4 (2KB). The threshold
value may not exceed 1/4 the total cache size or the specified value will be
ignored and the default value will be used instead. Any read operation that is
less than the threshold is read into the disk cache first. Therefore, subse-
quent read operations will probably find the needed data in the cache, thus
improving performance.

The following statement sets the FAT file system cache at 512KB with lazy
writing enabled and a threshold value of 64 resulting in the caching of all
reads < 32KB.

DISKCACHE=512,LW,64

BUFFERS=

Provides memory that OS/2 2.x uses to cache FAT directory information, thereby
improving performance. This usage is different than in a DOS environment. A
buffer is the size of a FAT sector (512 bytes), so every 8 buffers take one
page of memory. On larger FAT partitions, performance will be improved by
increasing the number of buffers.

The default value is 30.

IFS=

This statement causes the High Performance File System to be loaded. It is also
used to specify the size in KB of memory to allocate for the HPFS disk cache
(via the /CACHE parameter), and the threshold in KB for caching disk reads (via
the /CRECL parameter).

Note: If your system has no HPFS partitions defined, you should disable the
loading of HPFS by adding a REM to the beginning of the IFS= line in your
CONFIG.SYS.

Lazy writing for HPFS defaults to ON. A RUN=CACHE statement is required to
change the state of lazy writing. CACHE also can be executed from a command
prompt. See Figure 12jfor the default disk cache sizes and Figure 11 on page 25
for the other cache and lazy write options that are available.

The example that follows shows the default statement on 8MB systems. This
results in the allocation of a 512KB HPFS disk cache and in the caching of I/O
requests that are smaller than 4KB. The /AUTOCHECK parameter designates which
partitions should be CHKDSK'd at boot time. The C: partition is designated for
autocheck.

IFS=C:\OS2\HPFS.IFS /CACHE:512 /CRECL:4 /AUTOCHECK:C

The next example sets the HPFS cache at 2MB, and uses the default value of 4KB
for the cache record length threshold. No partitions are designated for
autocheck.

IFS=C:\OS2\HPFS.IFS /CACHE:2048

The next example sets the HPFS cache at 256KB and sets the cache record length
threshold at 16KB. The D:, E:, and F: partitions are designated for autocheck.

IFS=C:\OS2\HPFS.IFS /CACHE:256 /CRECL:16 /AUTOCHECK:DEF

This last example attempts to set both the HPFS cache size and the cache record
length threshold to 64KB. However, the CRECL value is invalid because OS/2 2.1
disk cache thresholds may not exceed 1/4 the total cache size. Therefore, the
system overrides the value and uses the HPFS default threshold of 4KB. The D:,
E: and F: partitions are designated for autocheck.

IFS=C:\OS2\HPFS.IFS /CACHE:64 /CRECL:64 /AUTOCHECK:DEF

PRIORITY_DISK_IO=

Specifies disk input/output priority for applications running in the
foreground. When PRIORITY_DISK_IO=YES is specified in the CONFIG.SYS file, an
application running in the foreground receives disk I/O priority over
applications running in the background. Therefore, the application in the
foreground has better response time than applications running in the
background.

An example of a time when this should be set to NO is if you are running an I/O
intensive application in the background (like a compile) and are working in the
foreground on a task that is less important to you than the compile. Setting
this to NO would remove the priority boost from the foreground application and
improve the performance of the background compile.

The default value is YES.

THREADS=

Specifies the maximum number of threads OS/2 will allow to exist at any one
time. Threads are dispatchable units of execution. OS/2 applications usually
have several threads to take advantage of multitasking. DOS and Windows
applications usually have only 1 thread. Some threads are used by the system.
The default is 128 or 256 threads, (depending on system memory at installation
time) which should be plenty for general use. Changing this value to an
unnecessarily large one in not advisable because it takes additional memory.
Reducing it below 128 does not significantly free any memory. The default value
should be acceptable in most environments. One exception is a server
environment, where it is generally better to have 256 or 512 threads on the
server.

The default value is 128 or 256 threads.

 MAXWAIT=

Sets the amount of time a ready-to-run regular or server class thread can wait
before the system assigns it a temporary higher priority. The amount of time to
set depends on the number of concurrent applications and the activities the
applications perform.

The default is 3 seconds.

This default value is optimal for most system setups.

TIMESLICE=

Sets the minimum and maximum amount of processor time allocated per timeslice.
This line does not appear in the default install of OS/2 2.x, since the system
defaults to dynamic time slicing based on system load and paging activity.
While this entry is supported, it should not be used.

The default is not in the CONFIG.SYS. DO NOT use this setting.

MEMMAN=

Specifies memory management control options. The SWAP option indicates that
swapping to the swap file is enabled and memory can be overcommitted. The
NOSWAP option prevents swapping. When NOSWAP is selected, the system must
contain physical memory for all memory allocations. SWAP should be selected.
The PROTECT option enables certain APIs to allocate and use protected memory.

The COMMIT option indicates that the memory manager should reserve storage in
the swap file at the time any memory is allocated. Specifying this option
causes very large swap files to be generated. It can be useful in unattended
operating environments (if you specify the COMMIT option, you should increase
the initial swap file size parameter on the SWAPPATH= statement).

The default value is SWAP,PROTECT.

PRINTMONBUFSIZE=

Sets parallel-port device driver character monitor buffer sizes for LPT1, LPT2
and LPT3. You may increase performance of data transfers to devices connected
to parallel ports by increasing the associated device driver monitor buffers
sizes. For example, to increase the size of the device driver buffer for a
device connected to parallel-port LPT1 to 2048 bytes, specify:
PRINTMONBUFSIZE=2048,134,134. Continue


ΓòÉΓòÉΓòÉ 8.4.2. Customizing(continued) ΓòÉΓòÉΓòÉ

The default value is 134,134,134 bytes

PROTECTONLY=

Selects one or two operating environments. The OS/2 operating system requires
this statement in the CONFIG.SYS file.

The PROTECTONLY=NO statement allows a user to run both DOS (including WIN-OS/2)
and OS/2 applications.

The PROTECTONLY=YES statement allows a user to run only OS/2 applications.

The default value is NO.

RMSIZE=

Specifies the highest storage address allowed for the DOS operating
environment. Leave the default for optimal performance in your VDM sessions.

The default value is 640KB.

SET DELDIR=

Specifies the location to hold deleted files, and the total size of files to be
retained. This allows you to save files that have been deleted, for later
retrieval if needed. By default, this setting is commented out because backing
up each deleted file slows system performance. When enabled, the last value is
the size in KB of files to be saved for restoring. The fol- lowing statement
enables restoring files to a total of 512KB, for the C: and D: partitions.

SET DELDIR=C:\DELETE 512;D:\DELETE 512;

This means that OS/2 will 'save' files erased, deleted or shredded from the C:
partition to a total of 512KB in the C:\DELETE subdirectory (those from the D:
partition would be 'saved' in the D:\DELETE subdirectory). FIFO management is
used. If the last file deleted is larger than 512KB, than that entire file is
saved, regardless of size. The system does not differentiate between files
erased by the user and files erased by an application (temp files).

Only use this function when you are cleaning your system, and ensure that you
have a large enough size specified to save all the files until you are
finished. Then REM out this statement in the CONFIG.SYS for the next boot.
Performance when erasing or moving files is slow with this feature enabled.

The default is disabled.

SET RESTARTOBJECTS=

Specifies the action to be taken by the Workplace Shell when the system is
rebooted. This line does not appear in the default install of OS/2 2.x, but the
system defaults as if a SET RESTARTOBJECTS=YES statement had been encountered.
This causes all objects in the Startup folder and any other objects that were
active when the system was last running to be started.

A SET RESTARTOBJECTS=NO statement indicates that nothing should be started.
This selection would provide the fastest boot time.

A SET RESTARTOBJECTS=STARTUPFOLDERSONLY statement indicates that only the
objects that are in the Startup folder should be started.

The default value is YES.

Changes for a DOS Session

Virtual device drivers used by DOS sessions take little or no memory below the
640KB limit.A user can install device drivers that are required by, and are
specific to, certain applications that run in a DOS session. If the commands to
load these device drivers or other memory resident programs are added to the
CONFIG.SYS file, these device drivers (or programs) are loaded into any DOS
session. This reduces the amount of conventional memory available to DOS
applications.

DOS settings allow a user to customize a DOS session. To ensure that the
maximum amount of memory is available in each DOS session, load the necessary
DOS device drivers for the DOS application by using DOS settings. For example:

DEVICEHIGH=

Loads a specified DOS device driver into an available upper memory block (UMB)
for a DOS session.

Note: DOS device drivers normally are loaded into low memory (below 640KB) in
DOS sessions.

If a UMB is not available, the device driver is loaded into low memory (as a
DEVICE= statement). To enable UMBs, include the DOS=UMB statement in the
CONFIG.SYS file.

DOS=

Specifies whether the DOS kernel will reside in the high memory area (HMA) and
whether the operating system or DOS applications will control upper memory
blocks.

Note: Upper memory blocks are provided by the XMS device driver.

It also is necessary to include a VXMS.SYS statement in the CONFIG.SYS file to
have upper memory blocks available.

o With a DOS=HIGH/LOW,UMB statement, the operating system controls the upper
  memory blocks. This means that DOS applications can be loaded into upper
  memory but cannot allocate UMBs.

o With a DOS=HIGH/LOW,NOUMB statement, the operating system will not control
  any UMBs. DOS applications can allocate UMBs but cannot be loaded there.
Eliminate DEVICE= statements for DOS device drivers from the CONFIG.SYS file
unless the device driver is required for any DOS session.


ΓòÉΓòÉΓòÉ 8.5. The AUTOEXEC.BAT ΓòÉΓòÉΓòÉ

Customizing

The AUTOEXEC.BAT file is specific to the DOS session and has no effect on the
OS/2 operating system. It can be customized for each session. This file
contains DOS system commands that run when a DOS session is started. The
AUTOEXEC.BAT file starts memory resident programs, such as network programs,
and sets up environment variables.

To make as much base memory as possible available to applications, remove any
unnecessary commands from the AUTOEXEC.BAT file. Create several AUTOEXEC.BAT
files. Include only the commands needed in each AUTOEXEC.BAT file to customize
a specific DOS session.

Note: Do not allow the installation of a DOS or Windows application to change
the AUTOEXEC.BAT file supplied with OS/2. If a DOS command is necessary for a
specific DOS application, customize the specific AUTOEXEC.BAT file for that DOS
session.


ΓòÉΓòÉΓòÉ 8.5.1. How To Specify a Different AUTOEXEC.BAT File ΓòÉΓòÉΓòÉ

You may start DOS or WIN-OS/2 sessions with the default AUTOEXEC.BAT file which
is located in the root directory of the boot drive. It is better to specify a
customized AUTOEXEC.BAT file to create the environment for running that
specific DOS or Windows application. The specification of the new AUTOEXEC.BAT
can be done by selecting the setting DOS_AUTOEXEC in the WIN-OS/2 Settings
notebook for the application object (Dos Settings). Also see Dos Settings.


ΓòÉΓòÉΓòÉ 8.6. Tuning for OS/2 Applications ΓòÉΓòÉΓòÉ

OS/2 applications are designed to run in the native OS/2 environment. Because
of this, special settings and configurations to support these applications are
not required. Well written OS/2 applications take advantage of OS/2 at the API
level. Users do not need to make explicit changes for OS/2 applications.


ΓòÉΓòÉΓòÉ 8.7. Tuning for Windows Applications ΓòÉΓòÉΓòÉ

 Enhanced and Standard Modes

The Enhanced Mode Compatibility enables the user to run a number of Windows 3.1
enhanced mode applications under OS/2 2.1. It is important to realize that this
is not an implementation of Windows 3.1 enhanced mode, but a mode specific to
WIN-OS/2 3.1 that illustrates the flexibility of OS/2 and its power in blending
different application environments into an integrated platform since the major
benefit to Windows 3.1 users of enhanced mode was virtual memory - something
which OS/2 users already have.

Like the previous WIN-OS/2 3.0, a special VDM is provided to emulate a DPMI
server and the WIN-OS/2 3.1 kernel is loaded into the VDM to directly service
the requests of Windows applications running in the VDM. To preserve the
integrity of the system and avoid having duplicate virtual device drivers (one
running on top of the other), the WIN-OS/2 3.1 Enhanced Mode Compatibility does
not use the Windows enhanced mode virtual device drivers (VxDs). As a result,
Windows 3.1 applications which do not access the VxDs, such as Mathematica,
OmniPage Professional and Vellum, will run in the WIN-OS/2 3.1 Enhanced
Compatibility Mode.

An application can be set up to run in the Enhanced Compatibility Mode by
setting the WIN_RUNMODE to "3.1 ENHANCED". This setting can be found in the
WIN-OS/2 Settings notebook for the application object. You can also start an
Enhanced Compatibility mode session from an OS/2 or DOS command line by typing
WINOS2 /E or WINOS2 /3

To start an application to run in the Enhanced Compatibility mode, for example
hello.exe, you would type WINOS2 /3 hello.exe.

An application can be set up to run in  Standard Mode  by setting the
WIN_RUNMODE to "3.1 STANDARD". This setting can be found in the WIN-OS/2
Settings notebook for the application object.

You can determine which mode is enabled in a VDM by bringing up the Help pop-up
menu from the Program Manager and select About.... The selection would display
the About Program Manager Box which will inform you if the session is in
Standard or Enhanced Compatibility Mode.


ΓòÉΓòÉΓòÉ 8.7.1. How To Install a WIN-OS/2 Application. ΓòÉΓòÉΓòÉ

You can select migration and the system will migrate your application, placing
the icon in the Windows Application folder. This is easiest as the system will
provide paths and some settings.

You can install a Windows application on the workplace shell by creating a
program object from the Templates folder and use the Settings Notebook for the
object to specify the settings for the application accordingly. For a Single
Application definition, enter the full path and file name of the application in
the Program Object definition. For a multiple application definition, enter the
name of the program manager, i.e., MYAPP.EXE, in the Program Object definition.
Once the program definition has been done, you can go to the Session Object to
specify the session type: WIN-OS/2 Full Screen or WIN-OS/2 Windowed. If you
select the WIN-OS/2 Windowed option then you can select the Separate option to
run your application in a separate VDM. If the option is not selected then it
will be run by default in a Common seamless session.


ΓòÉΓòÉΓòÉ 8.7.2. Starting DOS and OS/2 Applications from WIN-OS/2 ΓòÉΓòÉΓòÉ

The ability to start non-Windows applications from a VDM running WIN-OS/2 does
not exists under OS/2 2.0. In the release 2.1, you can now start DOS and OS/2
applications from a VDM running a WIN-OS/2 full screen or seamless session.

From a command prompt in a DOS VDM session, you can start an OS/2 application
by typing the name of the application as if the application was a DOS
application,.


ΓòÉΓòÉΓòÉ 8.7.3. Full Screen vs. Seamless Mode. ΓòÉΓòÉΓòÉ

By default, the WIN-OS/2 icon is set to full screen. Because it references * in
the program set- tings, you cannot easily change from full screen to seamless.
Some performance gain can be obtained by running your application under
WIN-OS/2 in a full screen. However, you may prefer to run in seamless mode. A
quick way to change from full screen to seamless is to change the WIN-OS/2
program settings path and file name to C:\OS2\MDOS\WINOS2\PROGMAN.EXE (assuming
C: is the partition where WIN-OS/2 is installed). This allows you to choose
either WIN-OS/2 Full Screen or WIN-OS/2 Windowed (seamless). To launch your
applications. (change the selection of full screen or seamless on the session
page of the icon settings) Change the icon title on the general settings page.


ΓòÉΓòÉΓòÉ 8.7.4. How to Load Your Application Faster in the Seamless ΓòÉΓòÉΓòÉ

Environment

An application can run in a common or separate sessions. Common seamless
sessions share one WIN-OS/2 kernel regardless of the number of applications
loaded. Separate sessions load a new copy of the WIN-OS/2 kernel each time an
application (or session) is started. As a result, if you launch an application
from a separate seamless session, the time taken to load the application
includes the time to load the WIN-OS/2 kernel as well. To eliminate the loading
time of the WIN-OS/2 kernel, you can either load a small Windows utility
program at the system startup time (e.g., loading clock.exe from the StartUp
folder), or before the actual loading of your main application.


ΓòÉΓòÉΓòÉ 8.7.5. How to Reduce Memory Management Overhead for WIN-OS/2 ΓòÉΓòÉΓòÉ

3.1

When a WIN-OS/2 session starts, the WIN-OS/2 kernel checks the settings of
DOS_RMSIZE and DPMI_MEMORY_LIMIT before committing the memory it would allocate
to the session. The new WIN-OS/2 3.1 kernel will allocate 1MB for the DOS
virtual machine and partially commit the DPMI memory that was asked for. By
adjusting the settings for DPMI memory, you can drastically reduce the overhead
associated with the memory management


ΓòÉΓòÉΓòÉ 8.7.6. How to Reduce Memory Resource Usage ΓòÉΓòÉΓòÉ

To reduce system memory resource usage, use a Common Seamless session whenever
possible since only one VDM will be started for all of the WIN-OS/2 Seamless
sessions.

Also, reduce the amount of EMS and XMS memory allocated to your sessions if
your applica- tion do not require it. While the session only allocates linear
address space, some applications try to touch all memory just to see what is
available. This will increase the memory required to run the application and
may increase the size of the swap file. If you are not sure if your
application(s) use EMS or XMS, then reduce the amounts from the default 2048 KB
to 64KB. This will provide enough memory for applications to run without
causing application failure with applications requiring EMS or XMS memory
support.


ΓòÉΓòÉΓòÉ 8.7.7. How to Improve Cut and Paste Operations ΓòÉΓòÉΓòÉ

New user interfaces are provided in WIN-OS/2 3.1 to enable specifying the
Clipboard and DDE as either "Public" or "Private". By default, both Clipboard
and DDE for both OS/2 and WIN-OS/2 are public, you can exchange data among
programs running in DOS, OS/2, and WIN-OS/2 sessions. If the WIN-OS/2 Clipboard
and DDE are set to private then the data exchange is only allowed among
programs running in the same WIN-OS/2 session.

There are two ways you can set the operating mode for the Clipboard and DDE.
You can select the operating mode of Clipboard and DDE for all WIN-OS/2
sessions through a new global WIN-OS/2 setup object in the Workplace Shell. For
local settings, effective only to the single VDM session, you can use the new
settings provided in the WIN-OS/2 Settings notebook page (WIN_CLIPBOARD &
WIN_DDE). If your application does not exchange data with a DOS or OS/2
application then you should set the Clipboard and DDE to private for better
performance.


ΓòÉΓòÉΓòÉ 8.8. WIN-OS/2 Settings ΓòÉΓòÉΓòÉ

Settings for WIN-OS/2 sessions can be changed globally, using the WIN-OS/2
Setup icon found in the System Setup folder. Settings can also be changed for
specific sessions, using the application settings notebook. Changes to the
WIN-OS/2 Setup icon will change all Windows applications that start after the
change is made. The WIN-OS/2 Setup settings will not override any custom values
set for applications. This allows you to change settings easier when you have
multiple applications.

There are two new settings for WIN-OS/2 3.1.

WIN_RUNMODE

In WIN-OS/2 3.1, the WIN_RUNMODE Settings option has been changed to include
two radio buttons for selecting either one of the two modes-- 3.1 Standard or
3.1 Enhanced Compatibility.

The default is Standard.

DOS_AUTOEXEC

The DOS_AUTOEXEC setting is new in WIN-OS/2 3.1. This setting allows the
application to run in different DOS environments. You can now specify the
AUTOEXEC.BAT file to be executed when the VDM session is started.

The default is blank, and the AUTOEXEC.BAT found in the root directory will be
used. There are several other settings that affect the performance of your
WIN-OS/2 session that are the same as in OS/2 2.0.

WIN_DDE

This setting allows WIN-OS/2 to share DDE information between WIN-OS/2 and OS/2
sessions. For better performance, this setting should be set OFF, but only if
you are not exchanging data via DDE between OS/2 and WIN-OS/2 applications.
This should be set to Off  for private data exchange between DOS applications.

The default is ON.

WIN_CLIPBOARD

This setting allows WIN-OS/2 to share clipboard information between public
WIN-OS/2 and OS/2 sessions.

For better performance this setting should be set to Off for private data
exchange between WIN-OS/2 applications. Only set this setting Off if you will
not be exchanging clipboard data between OS/2 applications and WIN-OS/2
applications.

The default is ON.

DOS_BACKGROUND_EXECUTION

Allows DOS applications to run in the background.

o When the setting is set to On  a Windows application runs when it is in the
  background.

o When the setting is set to Off  a Windows application is suspended when it is
  in the background.
When the Windows application is suspended, it no longer receives interrupts.
For example, if users have a polling application running on the background, it
may slow down the foreground application. Thus, the setting may be turned on to
gain the foreground performance.

The default is On.

VIDEO_8514A_XGA_IOTRAP

This setting is used to directly access the Model 8514/A or XGA video.

Setting this to Off  will make an application run faster. It releases the 1 MB
of allocated memory where video information is saved in a WIN-OS/2 session,
specifically when executing with the 8514/A display driver, certain operations
such as painting a dithered back- ground will run faster.

Set this to On  for all WIN-OS/2 sessions that run in 8514 or XGA video modes.

The default is Off.

VIDEO_SWITCH_NOTIFICATION

This setting is used to notify the DOS program when the session switches to or
from a full screen VDM session. WIN-OS/2 understands this notification and will
redraw the screen when the screen is switched. For WIN-OS/2 sessions, set the
to ON.

The default is On.

Note: This setting must be ON if the VIDEO_8514A_XGA_IOTRAP is set OFF.

INT_DURING_IO

Allows interrupts to be handled during file reads/writes. This setting is
primarily designed for DOS multimedia applications and should be turned on when
the user runs such applications.

The default value is Off.

DOS_RMSIZE

Defines the amount of conventional memory available to WIN-OS/2. This setting
is used to decrease the amount of available memory to less than 640 KB. Do not
decrease this value for WIN-OS/2 sessions.

The default value is 640 KB.

DPMI_MEMORY_LIMIT

Defines the amount of DPMI memory available to the WIN-OS/2 session. This
setting enables you to specify the amount of DPMI memory for the Windows
applications on a per session basis. The field for this setting contains values
expressed in megabytes.

The default value is 64 MB . The range is 1 to 512.


ΓòÉΓòÉΓòÉ 8.9. Tuning for DOS Applications ΓòÉΓòÉΓòÉ

Full Screen vs. Windowed

DOS applications (non-graphical) perform well in a windowed session. For
example, DOS file- intensive applications such as FoxPro 1.0 perform well while
running in a VDM windowed session. DOS word processors such as WordPerfect 5.1
and Word 5.0 also perform well in a windowed DOS session. DOS programs doing
intensive text or graphical display will run slower in a windowed session
compared to a full screen session. The main reason is that the full screen
session allows data to be directly written to video memory while the windowed
session does not.

Multitasking DOS sessions

OS/2 2.x allows users to run more than one VDM session. It provides the ability
for all DOS and OS/2 sessions to timeshare the CPU and other system resources.
It is important to note that DOS applications, unlike OS/2 applications, rarely
block. They consume CPU timeslices even if they are in the background or appear
not to be doing anything useful (e.g., polling keyboards or other devices.)
This is controlled by the DOS setting Idle_Sensitivity.

Some applications recommend that the idle sensitivity be set to a high value.
Those applications may contain functions that appear to OS/2 to be polling, and
the lower setting on idle sensitivity may cause a functional problem. If your
application has functions that appear to 'hang' when the idle sensitivity is
set low, increase idle sensitivity to a value where the function works
correctly.

Another option is to set the DOS_BACKGROUND_EXECUTION to Off. This makes the
foreground job and other OS/2 jobs run faster as there will be no background
DOS applications competing for the CPU usage. This also allows idle sensitivity
to be set higher than the default value, which improves the foreground DOS
application.

Running Interrupt-critical DOS sessions

Some DOS applications require fast and stable hardware interrupt support. For
instance, DOS communication programs need a steady data flow from COM ports.
Since the VDM session are virtualized, there are some inherent interrupt
limitations. For a DOS communication application, the data processing rate can
reach 9600 bps for a single-character buffer com port. This value is reduced
when running multiple communication application applications concurrently, to a
total of 9600 bps.

Similarly, DOS multimedia applications require constant timer interrupts. By
the nature of the VDM interrupt mechanism, interrupts may get simulated into
the application(s) not at constant time intervals but in a clustered fashion.
Therefore, if the DOS application depends on timer interrupts, you may
encounter some unpredictable behavior.


ΓòÉΓòÉΓòÉ 8.10. DOS Settings ΓòÉΓòÉΓòÉ

Every object (including program objects) has settings. You can adjust DOS and
WIN-OS/2 settings to improve performance. Settings are properties or
characteristics that tell the operating system how one object is different from
other objects. Each object has a notebook or pop-up menu choice that allows you
to customize settings.

For example, you can customize the settings for a program object to tell the
operating system how the application should start each time the program object
is opened. You might open the Mouse object to customize the mouse for left hand
use.

Performance Tuning

DOS settings provide the ability to selectively configure and customize a DOS
session to meet the requirements of a particular application. Some DOS
applications require certain features; others operate better without them.
Thus, an individual DOS session can be set up to provide the optimum
environment for the application that will run within it. All settings can be
changed before the session is created. Some settings can also be set at any
time, even while an application is running in the session. The Master Help
Index has detailed information about settings.

The following is a list of settings that affect the performance of your DOS
applications.

IDLE_SENSITIVITY

Specifies a threshold for judging when an application is considered idle. The
value is the percentage of the maximum possible polling rate the application
can perform. If an application polls at a rate higher than this value, it is
considered idle.

Idle detection is a "best guess" of what the program is doing. It could be that
the program is polling at a very high rate, but is still doing useful work in
between checking. It may be that the application checks at a fairly slow rate
but is doing nothing but waiting. The idle sensitivity threshold allows you to
adjust the threshold for each application.

Increase the percentage if the application can receive input while running and
seems to run more slowly than expected. Selecting 100 in this field turns idle
detection off, and the application can poll as often as necessary without
operating system intervention.

Be aware that polling applications are detected quicker on fast systems than on
slower systems. This means that the value on different speed systems must vary
-- decrease the value on faster systems. Example: If a polling DOS application
with idle_sensitivity set to 50 on a 33 MHz CPU is detected as exceeding the
threshold and forced to yield its timeslice by OS/2, it may not be detected as
exceeding the threshold on a 16 MHz system with the same idle-sensitivity
value. The 16 MHz system will need to set a lower value before OS/2 will
consider the same application as exceeding the threshold and cause a yield.

Overall system performance can usually be improved when there are multiple DOS
applications running if the value is set lower. For additional information on
the setting see Multitasking DOS sessions

The default value is 75. The range is 1 to 100.

IDLE_SECONDS

Specifies the length of time, in seconds, the operating system waits before
applying idle detection in a DOS session.

This setting works with the IDLE_SENSITIVITY setting to help control polling
DOS applications. You can increase this value if you have an application that
waits for input or at a prompt (like a game).

The default value is 0. The range is 1 to 60.

DOS_DEVICE

Adds or modifies information about DOS device drivers for the specified VDM, in
addition to the information specified in CONFIG.SYS.

This setting allows you to specify a specific device driver for a specific
application. This means that you do not have to load all DOS device drivers at
boot time, but instead you can have the device driver(s) loaded when the
application that uses it is started. You may add, change, or delete the device
drivers using this setting via the list provided. Device drivers should be
loaded with the DOS_DEVICE setting instead of in the CONFIG.SYS, unless you
want the device driver loaded for all DOS sessions. For example, a program to
support hardware such as a scanner may include a device driver that is needed
only for that particular program. This device driver should be loaded using the
DOS_DEVICE setting, not globally in the CONFIG.SYS.

The default has no drivers.

DOS_BACKGROUND_EXECUTION

Allows DOS applications to run in the background.

When the setting is set to On , the DOS application runs when it is in the
background. The setting may be turned OFF to gain foreground performance. When
the setting is set to Off  the DOS application is suspended when it is in the
background.

The default is On.

INT_DURING_IO

Allows interrupts to be handled during file I/O.

This setting is primarily designed for DOS multimedia applications and should
be turned On  when running a multimedia application. Other DOS applications
that do not require long file read/write should leave it Off  as it will cost
more memory and system overhead.

The default value is Off.

DOS_AUTOEXEC

Allows customizing the selection of an AUTOEXEC.BAT file. This allows setting a
specific AUTOEXEC.BAT file for each VDM session or each DOS application. This
allows you to customize the VDM autoexec, helping to reduce memory and optimize
function. Also see How To Specify a Different AUTOEXEC.BAT File 33 for
additional information.

The default is the AUTOEXEC.BAT file in the root drive.

VIDEO_RETRACE_EMULATION

Controls the frequency of video retrace.

A few DOS applications run more slowly with this setting set to On. Changing
this setting to Off increases performance, but screen switching is not as
reliable. When set to off, retrace occurs only at the interval specific to the
video mode of the running DOS application.

The default is On.

VIDEO_8514A_XGA_IOTRAP

This setting is used to directly access the Model 8514/A or XGA video. Setting
this to Off  will make an application run slightly faster. It releases the 1MB
of allo- cated memory where video information is saved in the DOS session.

The default is Off.

VIDEO_SWITCH_NOTIFICATION

Notifies a DOS graphics application about a switch between background and
foreground. When this setting is On , programs that monitor screen switching
will save or redraw the screen when the screen is switched.

The default is On

DOS_FILES

Specifies the maximum number of file handles which may be opened in a VDM.
Setting this value higher than the default may improve performance for
applications which use a large number of files. For example, DBase IV requires
a DOS_FILES setting of at least 40. Setting it higher than necessary reduces
the available memory. Refer to your application documentation for the
recommended value.

The default is 20 . The range is 20 to 255.

VIDEO_FASTPASTE

The fast paste setting is used to increase the speed of input other than the
keyboard (i.e. character Cut and Paste transfers).

Set this to On  to increase the character speed of Cut and Paste transfers.
Pasting into a DOS session or application will generally work. However, some
applications can fail when using fast pasting because they buffer key-strokes
in an internal buffer, which can overflow.

The default is Off.

DOS_FCBS

Specifies the maximum number of file control blocks (FCBs) which may be opened
by applications running in the VDM.
Note that this setting affects only DOS applications which use file-sharing.
Some applications use many FCBs, so this number should be set high. Refer to
your application documentation for the recommended value.

The default is 16. The range is 0 to 255.

DOS_FCBS_KEEP

Specifies the number of FCBs that will be protected against automatic closure.
This setting specifies the number of FCBs that are protected against automatic
closure. This may improve application performance.

The default is 8. The range is 0 to 255.

DOS_BREAK

The break setting is used when you want OS/2 to check for the Ctrl+Break or
Ctrl+C key combinations while an application is running. If you want to have
the option to interrupt a DOS batch file running in a VDM in a faster way, this
setting should be turned on. However, DOS applications will run slower when
this setting is set to On.

The default is Off.

VIDEO_ROM_EMULATION

Controls the emulation of video functions like WriteChar, WriteTTY, and
full-screen scroll for BIOS Int10 processing.

Leave this setting ON because the emulated functions enhance performance over
most manufacturers' ROM versions of the same functions.

Select Off only if video read-only memory (ROM) provides enhancements to these
video functions, or if your application uses Int10 functions which are not
emulated.

The default is On.


ΓòÉΓòÉΓòÉ 8.11. Memory  Tuning ΓòÉΓòÉΓòÉ

The OS/2 2.x CONFIG.SYS file specifies the operating system configuration and
installs device drivers and other memory resident applications. The OS/2 2.x
AUTOEXEC.BAT file is specific to the functioning of the DOS session. To
allocate additional memory to applications running in a DOS session, some
commands can be moved from the AUTOEXEC.BAT to settings. The following
describes what settings can be changed to maximize memory in a DOS session.
Also see the sections on CONFIG.SYS and AUTOEXEC.BAT.

DOS_HIGH

Determines whether DOS is loaded outside the 640K low memory address space.
Loading DOS into high memory allows more available memory for application code
and data within the 640KB address space.

The default is Off (DOS is loaded into low memory).

MEM_EXCLUDE_REGIONS

This setting is used to specify address ranges which should be protected from
use by EMS/XMS and direct access by applications. This setting is intended for
experienced users who understand the hardware. Note that if these ranges are
defined excessively, they will adversely impact the function and performance of
EMS and XMS services.

The default is blank.

MEM_INCLUDE_REGIONS

Specifies regions which should be made available to EMS/XMS. This setting is
used to specify some address ranges between RMSIZE and 1MB for use by EMS and
XMS.

If there is a hardware adapter in this range which you know is not going to be
used by a particular VDM session, then the address range used by the adapter
should be made available to EMS and XMS. This will improve the performance of
EMS and XMS services.

The default is blank.

HW_ROM_TO_RAM

Copies the Basic Input/Output System (BIOS) from ROM to RAM.
When this setting is set to On , applications might run faster due to the fact
that BIOS services run slightly faster in RAM than in ROM.

The default is Off.

VIDEO_ONDEMAND_MEMORY

Reduces swap space requirements for full screen VDMs. Selecting On allows a
full screen VDM to run without pre-allocating a virtual video buffer for
high-resolution graphics modes. Using this setting does not prevent execution
of graphics application. It means that allocation of the buffer is delayed
until it is needed. This can save a substantial amount of memory/swap space,
which might be important under certain low-memory conditions. It also enables
you to start a program quickly. If the allocation of a virtual video buffer for
a full screen VDM fails at the time the application changes video modes, the
sessions will be frozen and you must switch back to the shell to free memory.
Unless you are able to free memory from another session, you may be unable to
get the DOS application running again. This is a concern if the application
conains unsaved data.

The default is Off.

Performance considerations for DPMI: DPMI provides direct access by DOS
applications to > 1 MB of memory in protect mode. There is one setting that can
affect system performance.

DPMI_MEMORY_LIMIT

 jDefines the amount of DPMI available to a DOS session. This setting
enables you to specify the amount of DPMI memory needed for DOS applications on
a per session basis. The field for this setting contains the value in MBs
ranging from 0 to 512. The value may be0  if a DOS application does not need
DPMI.

The default value is 4MB.

Performance considerations for XMS: XMS provides compatibility for DOS
applications that require XMS. There are three settings that can affect
performance.

XMS_MEMORY_LIMIT

Specifies the amount of memory that a DOS session can allocate to XMS. This
setting is expressed in KB units, ranging from 0 to 16384.

Specifying a large number for the extended-memory limit can slow performance.
The default value is 2MB.

XMS_HANDLES

Specifies the number of XMS extended memory block (EMB) handles. A handle is
used with each XMS EMB. This number is required because XMS pre-allocates all
the handle spaces to be compatible with XMS specifications. This setting should
be used only if an application uses a large number of handles. Reducing this
number will reduce memory consumption. On the other hand, specifying a large
number of handles will increase memory consumption and adversely impact system
performance.

The default value is 32.

XMS_MINIMUM_HMA

Specifies the minimum High Memory Area (HMA) memory request allowed. This
setting allows fine tuning XMS. The High Memory Area is slightly less than 64KB
in size. Only one request can be handled in this area at a time. If a value is
set, then only an application that requests an equal or greater amount will be
allowed access to this memory. Subsequent requests and requests smaller that
the value set will not be satisfied.

The default value is zero , and is optimal in almost all conditions. The range
is 0 to 63KB.

Performance considerations for EMS: OS/2 2.x provides full EMS support for DOS
applications. As OS/2 2.x uses virtual memory to emulate the DOS EMS system,
there is some degree of performance degradation when running a DOS applications
involving EMS, compared to native DOS. Most of the overhead is due to the
management of large data structures within the virtual memory system. The
advantage of using virtual memory to emulate DOS EMS is that it allows large
expanded memory to be supported with little limitation from physical memory. In
some cases, DOS applications may declare more expanded memory than the total
size of the physical memory.

The following settings affect EMS performance:

EMS_MEMORY_LIMIT

Defines the amount of EMS available to the DOS session. This setting is
expressed in KB units, ranging from 0 to 32768.

The value should be0  if a DOS application does not need EMS. This might
improve per- formance. Programs generally state whether they use EMS on the box
or in the manuals. This setting enables you to limit the amount of EMS that an
application reserves, which prevents an application from allocating more memory
than necessary. A limit that is too high can slow performance.

The default value is 2MB. The range is 0 to 32768 in 16KB increments.

EMS_LOW_OS_MAP_REGION

Some programs can use remappable conventional memory. Others do not use this
feature. This setting allows advanced users to set the size of the remappable
conventional memory available in a VDM.

The default is 384KB. The range is 0 to 576 in 16KB increments.

EMS_HIGH_OS_MAP_REGION

In addition to the EMS page frame, some programs can use additional address
ranges to access expanded memory. This setting gives you the capability to
adjust the size of the additional EMS region.

The default is 32KB. The range is 0 to 96 in 16KB increments.


ΓòÉΓòÉΓòÉ 8.12. Improving Printing Performance ΓòÉΓòÉΓòÉ

Printing performance can be tuned by changes to printer and job property
settings, changes in the CONFIG.SYS and by using the spooler settings. Some of
these changes are generic and affect all printing. Some of the changes affect
only certain types of printing. Not all settings listed in this section are
available for all printers, but, if available, they do change the performance
of printing on your system.

Printer  Settings

Every object (including the print object) has settings. A user can adjust these
print settings to improve performance. In OS/2 there are Job Properties and
Printer Properties. Job Properties work in conjunction with the printer driver
object's Printer Properties. These settings can be found in the printer object
notebook. Not all settings are supported by all printers. Printer driver
settings include job properties such as orientation, fonts and resolution.
Queue options include printer specific format and print while spooling. Print
options includes start and stop times.

The choices you make for both printer properties and job properties will be
overwritten by applications that permit the specification of job properties on
a per-job basis. In this case you must check that the options are chosen
correctly within your application.

The following are properties that affect performance.

Memory (KB)

By specifying the amount of memory your printer has, the printer driver can
determine if compression is to be used. Compression reduces the amount of data
that has to go to the printer, improving performance.

Resolution

This option allows you to vary the resolution of your graphics printing. The
selections are usually presented in terms of "dpi" (dots per inch). The higher
the number the better quality your print will be. The drawback is that it will
also take longer to print. However, you can use a low number for draft output
and select the highest number for printing the finished version. A printer's
memory size can limit the resolution you can choose.

Compression

This option compresses graphic print data which has the advantage of faster
printing for most jobs that contain graphics. Two common types of compression
are G4 and TIFF Packbit Byte.

o G4

  This improves the printing of graphic data that does not have large numbers
  of alternating bits, for example, large areas that are filled with solid
  color. G4 is available on all IBM 4029 printers and IBM 4019 models that
  support Form Feed Time Out. The 4019 models do not support G4 when printing
  in landscape mode.


o TIFF

  This improves the printing of graphic data that consists mostly of repeating
  bytes, for example, large areas having one type of fill pattern.

Fast System Fonts

You can elect, via this option, to download (copy) OS/2 system bitmap fonts, to
the memory of your printer. They will be copied to the printer as a device
bitmap font. The advantage is that a device font uses a smaller spool file and
prints quicker than a font printed in raster (graphic font) form. If overlaying
system fonts with graphics, or if print output differs from that shown on the
screen, then disable this option.

Printer Patterns

Pattern filling commands will be directly sent to the printer instead of asking
the operating system to perform the pattern filling. This reduces the spool
file size for pages that contain dense graphics (shaded and patterned
rectangular areas), and large scaled text. These improve printing speed. This
option should not be used if printer output patterns must exactly match
patterns displayed on your screen, nor if there are overlapping shaded or
patterned graphics in your document.

HP-GL/2

This option enables HP-GL/2 output. This allows the supporting of many more
graphics commands in the printer. This will allow faster printing of graphic
objects such as lines and circles. This also reduces the spool file size and
helps to print more quickly. For faster output, enable Page Protection (which
may require additional printer memory) on both the printer and Printer
Properties dialog and use HP-GL/2.

Large Buffers

Large Buffers allow the printer drivers to use more of OS/2's memory in order
to speed up printing. Around 4 MB is used for printing so system memory should
be at least 8 MB. If this option is set to OFF, then smaller memory requests,
around 1 MB will be used con- serving memory. If you have less than 8MB of
system memory, then it is better _not_ to use this option.

Print While Spooling

The Print while spooling option allows the printer to start processing the
print job before the application has finished sending the entire job to the
spool queue. Print jobs formatted in printer-specific format (PM_Q_RAW) can
speed up printing by using Print While Spooling.

This "threading" will increase throughput but could cause timeout problems
while printing large files with images. To solve this problem you can disable
the Print While Spooling option or you can increase the timeout value setting
in the port object.

The default is On.

Start and Stop Time

Start Time and Stop Time can be entered for each print object. For example,
time settings for "lunch time", 12:00p - 12:50p, can be used which enables
printing when you are not there.


ΓòÉΓòÉΓòÉ 8.12.1. Fonts Impact Print Speed ΓòÉΓòÉΓòÉ

Fonts can be stored in several places. They can be built into the printer,
housed on a cartridge that's plugged into the printer, or reside on your system
and be downloaded to the printer as needed. When you use printer-based fonts,
whether built-in or on a cartridge, you can print faster than if you first have
to download them.

Fonts are either bitmapped or scalable. With a bitmapped font, each character
is stored as a collection of individual pixels, so you need a separate
definition for each point size. Scalable fonts, also called outline fonts, are
stored as algorithms.This means that the system can generate the font in any
size using the algorithm. Generating scalable fonts takes time. If you're using
one font in just one size to format an entire document, the extra time may be
hardly noticeable. If you're using a lot of different fonts, the time may be
considerable. You can use any combination of these font variations, bitmapped
or scalable, stored in the printer or in the computer.

Clearly, you'll get the fastest printing with bitmapped fonts stored in the
printer (see Fast System Fonts), and the slowest with scalable fonts stored in
your computer.

Despite the speed disadvantage, there are strong arguments for storing fonts on
your computer and for using scalable rather than bitmapped fonts. First, most
printers have room for only one or two font cartridges. So if you want to add
new fonts to your library, you have to switch cartridges when you want to use
them. It's easier and much more efficient to store them on your hard disk,
where they're all available at the same time. An advantage to scalable fonts is
that you're guaranteed to have the typeface available in any size you'll ever
need. Scalable fonts require far less storage space on-disk, or in your
printer, than a set of equivalent bitmapped fonts in a range of sizes.


ΓòÉΓòÉΓòÉ 8.12.2. OS/2 Spooled Printing ΓòÉΓòÉΓòÉ

Printing through the spooler will provide the best performance on your system.
Here are some settings that can affect printing performance, with suggestions.

OS/2 Spooler

For optimal performance, it is recommended that the OS/2 spooler always be
enabled. The spooler provides flexibility while optimizing the use of the
system's print resources. The

OS/2 spooler can print a job in the background while you continue using the
application. You can now set the spooler's print priority via the spooler
object setting. The OS/2 spooler can support a number of printers
simultaneously and can be configured so that jobs on a single queue can be
shared among all the printers. This load balancing, called pooling, is
particularly important in server environments and can be achieved without the
knowledge of your applications.

Jobs can also be reprioritized while they are waiting in the queue. For
example, an urgent job can be given a higher priority than other queued jobs or
can be selected to print next, see Changing a Print Job's Priority.

Spool Path

If print jobs are very large, you may assign a different spooler path (drive or
path) that has more space than your install drive. If your print usage is
heavy, you want to place the spool file on your fastest hard disk. The spool
path is a setting of the spooler object.

Print Priority

The OS/2 spooler now has a setting called Print Priority. This allows you to
vary the spooler's priority from low to high. The default setting allows
printing to be balanced with your use of the desktop and your applications. If
your application appears to be printing slowly, you may want to choose a
slightly higher value so that printing will complete faster. If you choose a
higher value, OS/2 will let print jobs print faster, but this may cause your
desktop or applications to respond slower. In a print environment where very
little on screen work is performed or where print performance is of utmost
concern, you should increase the value. Priority changes become effective when
you close the spooler object folder.

The default is 95.

Spool File Formats

There are two formats of spool file data. They are the standard (PM_Q_STD) or
the raw (PM_Q_RAW) spool file data formats. The standard format is much
preferred as it con- sumes much less disk space than the raw format file.
Having less data to send across the parallel port saves time in getting the
data into the printer's buffer. Network traffic is reduced if printing across a
LAN.

Changing a Print Job's Priority

Changing a print job's priority will cause that particular print job to print
before any other queued job. To do this, click on the print job you wish to
change. Use mouse button 2 to display its context menu, and then select print
next.

You can change the priority of a print job so that it can print before or after
other jobs queued. To do this, click on the print job you wish to
re-prioritize. Use mouse button 2 to display its context menu. Open Settings
and change the value in the Priority field.

Note: Once a job has started printing, it is no longer possible to change its
priority, the Settings option is not available.


ΓòÉΓòÉΓòÉ 8.12.3. Printing from DOS ΓòÉΓòÉΓòÉ

While there are no performance specific tuning options, there are two things to
check.

Do not use the LPTDD.SYS device driver unless necessary. (The DOS application
is using INT 21h and is not closing the LPT1 handle). This will slow down your
DOS printing performance.

The other is the DOS setting called PRINT_TIMEOUT. This is useful for DOS
applications which do not explicitly close their print jobs. This is the time
that OS/2 waits before forcing a print job to the printer. A timeout of 1 or 2
seconds is sufficient for small print jobs, such as copying the contents of the
screen. However, when printing large files, formatting documents, or running
calculations, the value must be set high enough to allow all print results to
reach the spooler before the time limit expires. If not, results go in two or
more spool files instead of one, and the resulting output may be
unsatisfactory.

The default time is 15 seconds.

Printing from WIN-OS/2

You should always keep the OS/2 Spooler enabled to get the most benefit out of
the OS/2 print subsystem. This will assure that even from the WIN-OS/2
environment, printing is done in a separate thread. You should also keep the
WIN-OS/2 Print Manager disabled unless you are using a COM attached printer.
That is, always keep the WIN-OS/2 Print Manager icon closed.

The OS/2 Spooler allows multithreading and can deal with huge print files, even
while you work in WIN-OS/2. Print jobs sent from any WIN-OS/2 application to a
parallel attached printer won't show up in the WIN-OS/2 Print Manager. In this
case if you need to view or manipulate these print jobs, use the correct OS/2
printer object on the Workplace Desktop.

o WIN-OS/2 Ports and Drivers

  You should direct application output to LPTn.OS2 (where n is 1,2,3) wher
  possible. LPTn refers to the physical printer port. LPTn.OS2 is a file which
  is intercepted by WIN-OS/2 and routed directly to the spooler. This will
  provide improved performance over the standard LPT port assignments.

  You should always install equivalent printer queues in the OS/2 Desktop for
  your WIN-OS/2 printers even if you are only going to print to them from
  WIN-OS/2. If there is no equivalent OS/2 printer driver available then use
  the IBMNULL.DRV printer driver found in the OS/2 printer object.

o WIN-OS/2 COM Attached Printer

  If you have a COM attached printer and you would like to have your print jobs
  spooled, then enable the WIN-OS/2 Print Manager. This should be the only
  reason for you to use the WIN-OS/2 Print Manager. Remember that print jobs
  directed to LPTn.OS2 and LPTn will still go through the OS/2 Spooler.


ΓòÉΓòÉΓòÉ 8.13. Improving COM Performance ΓòÉΓòÉΓòÉ

Changes can be made in both CONFIG.SYS and DOS_SETTINGS that can affect the
perform- ance of communications applications. You must check the settings as
they may affect other applications running concurrently. In general, the speed
of your system will also affect the ability of your communications program to
achieve high baud rates and to multitask. CPU intensive and disk intensive
foreground applications/operations will affect the performance of your
communications application when it is in the background.

The following settings will affect the performance of communications
applications:

 PRIORITY_DISK_IO

Changing PRIORITY_DISK_IO to NO in CONFIG.SYS will improve the performance of
communications applications running in the background that are doing disk I/O,
if there is foreground work being performed that is also doing disk I/O. See
the CONFIG.SYS, for additional information.

INT_DURING_IO

This DOS setting set to ON allows interrupts to be handled during file reads
and writes. This setting turned ON may help the performance of your
communications program that performs disk I/O that requires long read and write
operations.

See DOS Settings, 39 for additional information.

IDLE_SENSITIVITY

This DOS setting, set to 100, turns idle detection off, and the application can
now poll without operating system intervention.

See DOS Settings for additional information.

HW_ROM_TO_RAM

This DOS setting set to ON may speed up your DOS communication program because
it allows the operating system to copy BIOS from ROM to faster RAM which might
run the application faster because BIOS services will run faster in fast RAM
than slow ROM.

See DOS settings for additional information.


ΓòÉΓòÉΓòÉ 9. Does the Hardware Impact Performance on OS/2 ? ΓòÉΓòÉΓòÉ

Performance of any system can only be as good as the hardware and software work
together. Some hardware advantages must be exploited by the software to provide
the added function or improved performance. OS/2 attempts to exploit these
advantages. Other hardware advantages provide additional function or improved
performance without requiring specific software. To fully cover improving
performance of OS/2, some general hardware information is included here.

The three main areas where performance for any system can be bottlenecked are
memory, disk and CPU.

Memory bottlenecks occur when attempting to run more programs in memory than
there is actual system memory. The hardware allows operating systems to execute
beyond the real system memory by allowing paging  or swapping  Both paging and
swapping allow code and data to be moved from memory to disk. Paging is the
term used in virtual memory systems, and swapping is the term used in segmented
systems. As paging or swapping continue, system performance degrades as access
time to code or data written to disk now includes the disk access time required
to read back into memory information that was moved out. It probably also
required moving off to disk some information to make room for the returning
information. This activity can cause extremely poor performance.

Disk bottlenecks occur when the operating system or application(s) require
large numbers of disk accesses quickly. Since the hard disk must complete one
I/O request before starting the next request, multiple requests can start to
queue, causing poor performance. Between I/O requests the hard disk must move
the head from one location to the next. Hard drives use average seek time to
show overall performance for I/O operations. Smaller seek times provide faster
system response times for I/O requests.

CPU bottlenecks occur when multiple concurrent tasks require processor time.
Since operating systems like OS/2 allow concurrent processing among multiple
tasks, the likelihood of becoming CPU constrained is increased. Additional
processor speed (described in megahertz) will allow faster completion of CPU
requests.

As with any operating system, hardware limitations or advantages affect the
overall system performance. Processor speed, memory speed, hard drive access
time, instruction caches and data caches all influence performance. More
specific information on the impacts follow. Generally speaking, just adding
more memory may not be the answer to improving performance on a system.
Specifically on OS/2 2.1, the following generalities are true. On an 80386SX
system, greater performance overall will be realized by upgrading to an SLC, an
80386DX or an 80486 (or higher) processor. For disk I/O bound applications,
especially where the I/O requests are large (data bases, word processors) or
small but sequential (spread sheets, compilers), upgrading to a hard disk that
has on-board caching will improve performance. If a system is memory
overcommitted (swap file is > 4 times system memory), performance will improve
by adding more memory.


ΓòÉΓòÉΓòÉ 9.1. CPU ΓòÉΓòÉΓòÉ

Upgrading the CPU will improve performance in instruction intensive
applications (graphical intensive applications like CAD, computational programs
like a spread sheet recalculation). Performance improvements vary based on the
upgrade. Upgrading a PS/2 Model 56 SX or 57 SX to a 386SLC can double the
performance, and moving to a 486SLC can improve performance by 4 times for
compute bound tasks. The 80386SX has an internal data bus of 16-bits, therefore
32-bit instructions will become two instructions internally. Without any
instruction caching to buffer this, 32-bit instructions will perform slower
than 16-bit. This is the basic reason that OS/2 2.1 on an 80386SX system does
not show the same performance improvements that other processors show.

If you have a system where your performance is not acceptable, and the system
is an 80386SX, upgrading the CPU will provide performance improvements. Adding
memory on 80386SX systems does not appreciably improve the overall system
performance. If the additional memory is not on the system board, then
performance may be slowed even further.


ΓòÉΓòÉΓòÉ 9.2. Memory ΓòÉΓòÉΓòÉ

Memory is generally available on the system board, in SIMMs and/or on adapter
cards. The speed of the memory is expressed in nanoseconds, and the lower the
value the better.

While memory speed itself is important (faster memory provides faster access to
information stored there), installation is also. Memory on the system board (or
planar) can be accessed by the processor faster than memory located on an
adapter card. The adapter card memory requires access through the system bus,
slowing down the time from processor to memory.

Having adequate memory in a system will also reduce the disk access because
paging or swapping is decreased. If OS/2 does not have to handle paging I/O
requests along with application I/O requests, system performance will improve.
If the swap file is large, and changing from one application to another results
in I/O requests, the system would benefit from additional memory.


ΓòÉΓòÉΓòÉ 9.3. Displays ΓòÉΓòÉΓòÉ

OS/2 2.1 supports the displays of VGA, XGA, SVGA, 8514, CGA, and EGA. Video
Graphics Array (VGA) was introduced by IBM in 1987 as the base video for all
IBM PS/2 systems. At the same time, the IBM 8514 Display Adapter/A was
introduced to meet customer requirement for high-resolution graphics. Extended
Graphics Array (XGA) is the latest IBM solution to high-resolution graphics. It
has employed many new technology advances and is a good choice for high
performance display. To compete with IBM's VGA standard, many manufacturers of
video adapter cards formed the Video Electronics Standards Association (VESA)
to promote higher-resolution, more-color displays. Video modes supported by
VESA are often called Super VGA (SVGA). Though CGA and EGA are supported by
OS/2 2.1, due to the limited display capabilities, they are not recommended.


ΓòÉΓòÉΓòÉ 9.3.1. VGA ΓòÉΓòÉΓòÉ

VGA has existed long enough that almost every video adapter card and monitor is
highly com- patible with the VGA specifications. The resolutions available in
OS/2 2.1 are 640 x 480 x 16 colors, and 320 x 200 x 256 colors. VGA mode is
also supported on XGA and SVGA display adapters.


ΓòÉΓòÉΓòÉ 9.3.2. SVGA ΓòÉΓòÉΓòÉ

OS/2 2.1 supports several SVGA chip sets. See Display  Selection, ET4000 is
widely used in display adapters, e.g., ProDesigner IIs by Orchid Technology
Inc., PowerGraph VGA by STB Systems, Inc., and some IBM PS/1 and ValuePoint
systems. Compared with XGA subsystems, these SVGA display adapters provide an
inexpensive alternative to high-resolution graphics, but the performance is not
as good as XGA. The SVGA drivers shipped with OS/2 2.1 are 256 color drivers
with three different resolutions. With 0.5 MB VRAM, you can only run in 640 x
480 x 256 color mode. 1.0 MB VRAM is required to run in 800 x 600 x 256 and
1024 x 768 x 256 color modes. As you might expect, higher resolutions lead to
slower performances.

Additionally, the OS/2 SVGA display drivers are generic device drivers, and are
not optimized for any particular video adapter. The supplied drivers may be
used with adapters that have the supported chip sets. The manufacturer's driver
may be optimized to provide better video performance on their specific
hardware. However, the vendor drivers may not support all the functionality of
the OS/2 drivers, such as seamless, OS/2 Palette Management, Multimedia
support, etc.


ΓòÉΓòÉΓòÉ 9.3.3. XGA & XGA-2 ΓòÉΓòÉΓòÉ

XGA is IBM's current standard for high-resolution graphics. Instead of the
Dynamic RAM (DRAM) used in most VGA subsystems, XGA has employed the Video RAM
(VRAM) technology, which allows the XGA display controller update the video
data in the VRAM simultaneously while the VRAM is busily refreshing the
display. With the new Hardware Drawing Assist functions, the XGA display
controller can directly draw the data stored in video display buffer. These
functions allow lines to be drawn, blocks of data to be moved (Bit-Blt), and
areas of color to be filled in on the display. With 0.5 MB VRAM, XGA can run in
640 x 400 x 256, 640 x 480 x 256, and 1024 x 768 x 16 color modes. It requires
1.0 MB VRAM to run in 1024 x 768 x 256 color mode.

The new XGA-2 subsystem offers more resolutions and faster performance than the
original XGA. The major hardware improvements include external polling,
non-interlace support, and faster VRAM. With external polling, graphics
coprocessor status can be retrieved without interrupting the current
processing.

The new XGA driver in OS/2 2.1 has made use of this new technology and
performance is greatly enhanced. The ability of XGA-2 to display high
resolution screens at non-interlaced refresh rates of up to 75Hz reduces
flicker while enhancing usability and providing potential productivity gains.
With the XGA-2 subsystem, OS/2 2.1 can display up to 65,536 colors in low
resolution modes (640 x 480 and 640 x 400) as well as all the resolutions
supported in XGA.


ΓòÉΓòÉΓòÉ 9.3.4. 8514 ΓòÉΓòÉΓòÉ

8514 is IBM's old standard for high-resolution graphics. Several non-IBM
display adapters, e.g., 8514 Ultra by ATI, also provide 8514 support. The
driver shipped with OS/2 2.1 is the 16-bit driver shipped with OS/2 2.0. You
can only run in 1024 x 768 x 256 color mode. With the 16-bit driver and the new
32-bit graphics engine, conversion overhead between these two components is
inevitable. The performance is slightly slower when compared with OS/2 2.0.


ΓòÉΓòÉΓòÉ 9.4. Hard Drives ΓòÉΓòÉΓòÉ

Hard drives, or fixed disks, affect the performance of boot time and
application load time, as well as the performance of I/O intensive
applications. Hard disk speed is expressed in average seek time, and the lower
number the better. Faster seek times reduces the amount of time an operating
system or application must wait until the requested data is returned. The
following example shows information on 3 SCSI hard disks. Notice the increased
transfer rate on the disk with only 1 ms faster average seek time.

Formatted Capacity(MB)      40       80      160
Average Seek Time(ms)       17       17       16
Data Transfer rate(MB/sec    1.35     1.35     1.50
Average Latency(ms)          8.3      8.3      8.3
Sector interleave            1:1 1:11:1
Interface                    SCSI     SCSI     SCSI

When upgrading your system, check the average seek time of the hard disk. Be
certain to weigh larger disk space and average seek time against cost to
determine the best hard disk for your system.


ΓòÉΓòÉΓòÉ 9.4.1. Hard Disk Caches ΓòÉΓòÉΓòÉ

Hard disks or disk adapters can provide caching for I/O requests. Generally, an
entire track is read into the cache memory and the data requested is
transferred from that memory into system memory. Because an entire track has
been read, there is less loss in head movement and rotational delay.
Additionally, the next I/O request may be satisfied from the hard disk cache
and the disk access time is removed. The greatest performance for cached DASD
is seen in sequential I/O requests. Random, small size requests also see an
advantage if more than 1/3 of the requests can be satisfied from the cache
rather than reading from the disk. This is determined by the way the
application accesses the data, and is generally not controlled by you.

When upgrading your system, cached hard disks will generally provide petter
performance overall.


ΓòÉΓòÉΓòÉ 9.4.2. Multiple Hard Disks ΓòÉΓòÉΓòÉ

Some hard drive types cannot support multiple hard disks. Of the ones that do,
only SCSI drives can handle concurrent I/O requests in multiple drives. This
means that on a system with 3 SCSI drives, OS/2 can potentially overlap 3 I/O
requests (one per drive). This improves performance in I/O intensive scenarios
when disk requests are correctly balanced.


ΓòÉΓòÉΓòÉ 9.4.3. Parallel Printing ΓòÉΓòÉΓòÉ

OS/2 provides support for advanced parallel port hardware. If the machine
supports Micro Channel and uses Direct Memory Access (DMA) for its parallel
port, then OS/2's Print Device Driver (PRINT02.SYS) significantly improves the
speed in which data is sent to the printer, in excess of 100 KB per second.
This allows OS/2 to improve print performance as well as spending more time
running applications because of the DMA's quickness.


ΓòÉΓòÉΓòÉ 9.4.4. Communications ΓòÉΓòÉΓòÉ

Machines with a buffered UART (for example NS16550A) will have better
performance than machines without buffering (for example NS16450).


ΓòÉΓòÉΓòÉ 10. Top Tips to Improve Performance ΓòÉΓòÉΓòÉ

This is a list of the top 13 performance tips for OS/2 2.1 MEMORY CONSTRAINED
(4 meg) and/or 80386SX systems.

 1. Disable Animation
 2. Eliminate all extraneous processes (clock, CPU meters)
 3. Only use FAT file system
 4. Remove IFS= line for HPFS (if not used)
 5. Upgrade processor and/or memory as needed
 6. Minimize apps & folders between uses (rather than close and reopen)
 7. Remove unused device drivers from CONFIG.SYS
 8. Leave diskcache at 128 KB
 9. Limit the number of concurrent applications
10. Limit background processing when working in the foreground
11. Limit communication BAUD rate
12. Limit concurrent spooling
13. Optimize all paths in CONFIG.SYS

This is a list of the top 7 performance tips for OS/2 2.1 SMALL DASD systems.

 1. Increase Available Memory

 2. Only use FAT file system

 3. Remove IFS= line for HPFS (if not used)

 4. Add memory

 5. Leave diskcache at 128 KB

 6. Spool from 1 Application at a time

 7. Use List of Tips for Memory Constrained

This is a list of the top 7 performance tips for Windows applications

 1. Tune WIN-OS/2 settings

 2. Tune DOS session settings

 3. Run multiple applications in one session (common)

 4. Leave the Windows Spooler Disabled

 5. Verify Adequate Amount of DPMI Memory

 6. Reduce EMS & XMS memory allocations to 64K

 7. Start Applications from the Icons

This is a list of the top 8 tips for large, multitasking systems

 1. Verify the swap file is the correct size at boot time.

 2. Use HPFS on large, busy disks.

 3. Tune the file system caches(use SPM/2)

 4. Tune DOS and Windows session settings

 5. Use 32-bit applications

 6. Startup LAN and Comm from their Directory

 7. Replace Startup.cmd with the Startup Folder

 8. Optimize the Desktop


ΓòÉΓòÉΓòÉ 11. Application Performance Measurements ΓòÉΓòÉΓòÉ

The charts for this appendix will not be available until after OS/2 2.1 ships
and the results are collected and charted. Look to IBM market tools and on
CompuServe for these files.


ΓòÉΓòÉΓòÉ 12. Display Driver Performance ΓòÉΓòÉΓòÉ

The charts for this appendix will not be available until after OS/2 2.1 ships
and the results are collected and charted. Look to IBM market tools and on
CompuServe for these files.


ΓòÉΓòÉΓòÉ 13. Removing Features ΓòÉΓòÉΓòÉ

Sometimes, features are installed and later you would like to move them off to
a server to reduce disk requirements, or you may wish to remove them. Here is a
list of the files associated with some of the features and applets that can be
deleted from your hard drive.

o Advanced Power Management (APM)

  Used on on those systems that contain the required hardware, usually notebook
  type systems.

  \OS2\APM.SYS

o Bitmaps

  These are extra bitmaps provided for background display.

  \OS2\BITMAP\SWAN.BGA \OS2\BITMAP\LIGHTHOU.VGA

o CID

  These files are used for LAN installation of OS/2.

  \OS2\INSTALL\SEDISK.EXE
  \OS2\INSTALL\SEINST.EXE
  \OS2\INSTALL\SEIMAGE.EXE
  \OS2\INSTALL\SEMAINT.EXE

o Command Reference

  This file is the system command reference (on-line help).

  \OS2\BOOK\CMDREF.INF

o High Performance File System

  These are the files associated with HPFS.

  \OS2\CACHE.EXE
  \OS2\DLL\STARTLW.DLL
  \OS2\HPFS.IFS \OS2\DLL\UHPFS.DLL

o Linker

  The linker files are used by application developers to link
  compiled/assembled files into programs. End users not developing applications
  might wish to delete these files.

  \OS2\RCPP.ERR
  \OS2\RC.EXE
  \OS2\LINK.EXE
  \OS2\RCPP.EXE
  \OS2\LINK386.EXE

o PCMCIA Support

  PCMCIA support may not be needed on your system. You can remove this file.

  \OS2\PCMCIA.SYS

o REXX

  End users that do not need REXX support can delete these files.

  Note: REXX support is required for IBM Communication Manager Support.

  \OS2\REXXTRY.CMD
  \OS2\DLL\PMREXX.DLL
  \OS2\PMREXX.EXE
  \OS2\DLL\REXX.DLL
  \OS2\RXQUEUE.EXE
  \OS2\DLL\REXXAPI.DLL
  \OS2\RXSUBCOM.EXE
  \OS2\DLL\REXXINIT.DLL
  \OS2\REX.MSG
  \OS2\DLL\REXXUTIL.DLL
  \OS2\REXH.MSG
  \OS2\HELP\PMREXX.HLP
  \OS2\BOOK\REXX.INF

o RIPL

  These files are used for remote IPL.

  \OS2\HELP\RIPLINST.HLP
  \OS2\INSTALL\RIPLINST.EXE

o Tutorial

  These file are used by the tutorial. If you have completed the tutorial and
  would like to delete it, you can remove these files.

  \OS2\TUTORIAL.EXE
  \OS2\HELP\TUTORIAL.HLP ,br \OS2\DLL\TUTDLL.DLL

o Chess

  These are the files for the chess applet.

  \OS2\APPS\OS2CHESS.BIN
  \OS2\APPS\DLL\CHESSAI.DLL
  \OS2\APPS\OS2CHESS.EXE
  \OS2\HELP\OS2CHESS.HLP

o EPM

  These are the files for the enhanced editor applet.

  \OS2\APPS\BOX.EX
  \OS2\APPS\MATHLIB.EX
  \OS2\APPS\DRAW.EX
  \OS2\APPS\PUT.EX
  \OS2\APPS\E3EMUL.EX
  \OS2\APPS\EPM.EXE
  \OS2\APPS\EPM.EX
  \OS2\APPS\DLL\ETKE551.DLL
  \OS2\APPS\EPMLEX.EX
  \OS2\APPS\DLL\ETKR551.DLL
  \OS2\APPS\EXTRA.EX
  \OS2\APPS\DLL\ETKTHNK.DLL
  \OS2\APPS\GET.EX
  \OS2\HELP\EPM.HLP
  \OS2\APPS\HELP.EX
  \OS2\HELP\EPMHELP.QHL

o Jigsaw

  These are the files for the jigsaw applet.

  \OS2\APPS\JIGSAW.EXE
  \OS2\HELP\JIGSAW.HLP

o Klondike

  These are the files for klondike (solitaire).

  \OS2\APPS\CARDSYM.FON
  \OS2\DLL\KLONBGA..DLL
  \OS2\APPS\KLONDIKE..EXE
  \OS2\HELP\KLONDIKE..HLP

o NEKO

  These are the files for neko (the cat).

  \OS2\APPS\NEKO..EXE
  \OS2\HELP\NEKO..HLP
  \OS2\DLL\NEKO..DLL

o PICVIEW

  These are the files for picview.

  \OS2\APPS\PICVIEW..EXE
  \OS2\HELP\PICVIEW..HLP
  \OS2\APPS\DLL\PICVIEW..DLL

o PMChart

  These are the files for the PM Chart productivity aid.

  \OS2\APPS\FASHION..DAT
  \OS2\APPS\INVEST..GRF
  \OS2\APPS\GREEN..DAT
  \OS2\APPS\DLL\MGXLIB..DLL
  \OS2\APPS\INVEST..DAT
  \OS2\APPS\DLL\MGXVBM..DLL ,br \OS2\APPS\PMCHART..EXE
  \OS2\APPS\DLL\PMFID..DLL
  \OS2\APPS\FASHION..GRF
  \OS2\HELP\PMCHART..HLP
  \OS2\APPS\GREEN..GRF

o PM Diary

  These are the files for the PM Diary productivity aid.

  \OS2\APPS\PMDALARM..EXE
  \OS2\APPS\PMDTODO..EXE
  \OS2\APPS\PMDCALC..EXE
  \OS2\APPS\PMDTUNE..EXE
  \OS2\APPS\PMDCALEN..EXE
  \OS2\APPS\PMMBASE..EXE
  \OS2\APPS\PMDDARC..EXE
  \OS2\APPS\PMSPREAD..EXE
  \OS2\APPS\PMDDIARY..EXE
  \OS2\APPS\PMSTICKY..EXE
  \OS2\APPS\PMDLIST..EXE
  \OS2\APPS\DLL\PMDIARY..DLL
  \OS2\APPS\PMDMONTH..EXE
  \OS2\APPS\DLL\PMDIARYF..DLL
  \OS2\APPS\PMDNOTE..EXE
  \OS2\APPS\DLL\PMSTICKD..DLL
  \OS2\APPS\PMDTARC..EXE
  \OS2\HELP\PMDIARY..HLP

o PM Seek

  These are the files for the PM Seek productivity aid.

  \OS2\APPS\PMSEEK..EXE
  \OS2\HELP\PMSEEK..HLP
  \OS2\DLL\PMSEEK..DLL

o Pulse

  These are the files for the pulse applet (CPU meter).

  \OS2\APPS\PULSE..EXE
  \OS2\HELP\PULSE..HLP

o Reversi

  These are the files for reversi.

  \OS2\APPS\REVERSI..EXE
  \OS2\HELP\REVERSI..HLP

o Scramble

  These are the files for scramble.

  \OS2\APPS\SCRAMBLE..EXE
  \OS2\DLL\SCRLOGO..DLL
  \OS2\DLL\SCRAMBLE..DLL
  \OS2\HELP\SCRAMBLE..HLP
  \OS2\DLL\SCRCATS..DLL

o SoftTerm

  These are the files for SoftTerm (the terminal emulator).

  \OS2\APPS\ACSACDI..DAT
  \OS2\DLL\OPROFILE..DLL
  \OS2\APPS\CTLSACDI..EXE
  \OS2\DLL\ORSHELL..DLL
  \OS2\APPS\SOFTERM..EXE
  \OS2\DLL\OSCH..DLL
  \OS2\APPS\CUSTOM..MDB
  \OS2\DLL\OSIO..DLL
  \OS2\APPS\SASYNCDA..SYS
  \OS2\DLL\OSOFT..DLL
  \OS2\APPS\SASYNCDB..SYS
  \OS2\DLL\OTEK..DLL
  \OS2\DLL\CTLSACDI..DLL
  \OS2\DLL\OTTY..DLL
  \OS2\DLL\OACDISIO..DLL
  \OS2\DLL\OVIO..DLL
  \OS2\DLL\OANSI..DLL
  \OS2\DLL\OVM..DLL
  \OS2\DLL\OANSI364..DLL
  \OS2\DLL\OVT..DLL
  \OS2\DLL\OCHAR..DLL
  \OS2\DLL\OXMODEM..DLL
  \OS2\DLL\OCM..DLL
  \OS2\DLL\OXRM..DLL
  \OS2\DLL\OCOLOR..DLL
  \OS2\DLL\SACDI..DLL
  \OS2\DLL\OCSHELL..DLL
  \OS2\DLL\SAREXEC..DLL
  \OS2\DLL\ODBM..DLL
  \OS2\DLL\SACDI..MSG
  \OS2\DLL\OFMTC..DLL
  \OS2\HELP\ACDISIO..HLP
  \OS2\DLL\OIBM1X..DLL
  \OS2\HELP\ANSI364..HLP
  \OS2\DLL\OIBM2X..DLL
  \OS2\HELP\ANSIIBM..HLP
  \OS2\DLL\OKB..DLL
  \OS2\HELP\IBM31011..HLP
  \OS2\DLL\OKBC..DLL
  \OS2\HELP\IBM31012..HLP
  \OS2\DLL\OKERMIT..DLL
  \OS2\HELP\IBMSIO..HLP
  \OS2\DLL\OLPTIO..DLL
  \OS2\HELP\SOFTERM..HLP
  \OS2\DLL\OMCT..DLL
  \OS2\HELP\TTY..HLP
  \OS2\DLL\OMRKCPY..DLL
  \OS2\HELP\VTTERM..HLP
  \OS2\DLL\OPCF..DLL
  \OS2\HELP\XRM..HLP
  \OS2\DLL\OPM..DLL

o Touch

  These are the files for Touch.

  \OS2\TOUCO21D..BIN
  \OS2\DLL\TCP..DLL
  \OS2\TOUMOU..BIO
  \OS2\DLL\TOUCALLS..DLL
  \OS2\CALIBRAT..DAT
  \OS2\HELP\TCP..HLP
  \OS2\CALIBRAT..EXE
  \OS2\MDOS\VTOUCH..COM
  \OS2\TOUCH..INI
  \OS2\MDOS\VTOUCH..SYS
  \OS2\PDITOU01..SYS
  \OS2\MDOS\WINOS2\SYSTEM\TOUCH..DRV
  \OS2\PDITOU02..SYS
  \OS2\SYSTEM\TDD..MSG
  \OS2\TOUCH..SYS
  \OS2\SYSTEM\TDDH..MSG
  \OS2\CALIBRAT..TXT
  \OS2\SYSTEM\TDI..MSG
  \OS2\DLL\FSGRAPH..DLL
  \OS2\SYSTEM\TDIH..MSG


ΓòÉΓòÉΓòÉ 14. Performance Tools ΓòÉΓòÉΓòÉ

A number of tools are available that can be useful in evaluating and tuning the
performance of your OS/2 2.x system.

SPM/2 - System Performance Monitor/2 - IBM Corp.

SPM/2 2.0 is an integrated package of powerful facilities that allow you to
monitor resources such as CPU, RAM, disk and more on your local and remote IBM
Operating System/2 2.0. SPM/2's ability to graph this resource information
allows you to look at real time data as well as saved data for any monitored
workstation in your LAN.

o Collects critical resource utilization data: CPU, memory, files, swap file,
  FAT/HPFS cache, physical disk, printer and communication port

o Records performance data to disk for processing at a later time.

o Collects data from multiple nodes in a single recording session.

o Provides a real-time graphical representation of how system resources are
  being used (CPU, disk, RAM and swap activity) as well as the ability to
  playback previously recorded data.

o Produces detailed resource utilization reports (from recorded data) that can
  be summarized by workstation, application, process or thread.

o Provides in-depth OS/2 2.0 memory analysis information (including working set
  and a view of OS/2 control blocks).

o Monitoring of remote OS/2 LAN Requester as well as Servers.

Performance 2.1 by Clear and Simple, Inc.

This tool is a simple aid to tune your system. It is excellent for the novice
user. It provides a way to change the CONFIG.SYS and to remove some file to
free DASD>

Pulse

Pulse is one of the simplest tools available for monitoring performance. It
generates an EKG-like graphic display that shows the level of CPU activity.
This tool can be found in the OS/2 Productivity Aids folder.

CPU Monitor - BONAMI SOFTWARE CORPORATION

A powerful combination of performance and analysis tools for the OS/2 user. Via
Presentation Manager graphics, CPU Monitor displays Real-Time information for
estimated CPU utilization, OS/2 process relationships and more. Dynamically
suspend and resume execution for individual threads. Helps you detect and stop
runaway, invisible and background programs.

OSRM2 - OS/2 Resource Monitor - C.O.L. Consulting, Ltd.

An integrated group of applications for tracking (real time monitor) and
performing capacity planning functions (analysis and modeling) for machine
resources (CPU, Disk, Memory, applications).

Bridge/Monitor - Bridge Technology Inc.

Bridge/Monitor is an OS/2 performance analysis and reporting tool, for large
enterprise LANs, that allows the user to remotely monitor and manage the
performance of the LAN. Performance bottlenecks are identified and alerts
generated in realtime when user defined thesholds are exceeded. A complete
performance database with query capability is maintained for reporting, trend
analysis and capacity planning. BRIDGE/MONITOR's proprietary communications
method enables peer-to-peer services between devices in the network.

Triplecheck - International OS/2 USER GROUP

A three-in-one monitoring utility. SwapMON monitors the size of the swapper
file. The free space on the swapper drives and displays the largest contiguous
block of memory. MON is an idle-time monitor displaying in graphics form the
amount of processor activity over a selectable timespan can be used to monitor
background activity. Clock displays concurrent date or time in analogue or
digital format. On-line context-sensitive help available for each program.


ΓòÉΓòÉΓòÉ 15. Files that can be Migrated to the Server ΓòÉΓòÉΓòÉ

This file contains information about which files are required on a LAN
Requester and which can be migrated to a Server machine. Read carefully. In
some cases, it is easier to list what files must remain, and in other cases it
is easier to list what can be moved. Tests were performed to move files off a
requester machine onto a server, boot the requester machine, and then perform
basic operations, functions, and applications.

When files are moved to a server machine, remember that the LIBPATH, PATH, and
DPATH statements in the requester's (client) CONFIG.SYS file should be updated
with the SERVER directory where these files were moved. Do NOT delete any OS/2
system directory entries in these path statements even if they are empty. If
empty, they should be moved to the end of the path statements. For any
applications that appear in folders, such as:

o STHR..EXE in the Start Here icon on the OS/2 Desktop

o E..EXE in the Productivity Folder

o All of the Applets and games in the Productivity and Games folders.

You must update the Settings to point to the correct drive and sub-directory:

 1. \OS2

    Following is a list of files that SHOULD REMAIN in the \OS2 sub-directory.
    Most of these files are for device drivers, hardware support and system and
    user INI files. Some of the .SYS and .DMD files may not reside in your \OS2
    sub-directory depending upon the type of install you performed and what
    hardware is installed on your system. The CACHE.EXE and HPFS.IFS files are
    required if you are using HPFS in your system. UNPACK.EXE is included in
    case you need to retrieve a file from the installation diskettes.
    CHKDSK.COM is included if Autocheck is specified for the file systems upon
    system boot up. The ATTRIB.EXE file is included because it may be needed by
    certain support functions.

    IBM2ADSK.ADD
    OS2DASD.DMD
    ABIOS.SYS
    IBM2FLPY.ADD
    OS2SCSI.DMD
    CLOCK02.SYS
    IBM2SCSI.ADD ,br ATTRIB.EXE
    COM.SYS
    000000.BIO
    CACHE.EXE
    DOS.SYS
    F80D00.BIO
    CMD.EXE
    EXTDSKDD.SYS
    F80D01.BIO
    PMREXX.EXE
    LOG.SYS
    W020100.BIO
    PMSHELL.EXE
    MOUSE.SYS
    W020101.BIO
    SVGA.EXE
    KBD02.SYS
    W050000.BIO
    UNPACK.EXE
    PCLOGIC.SYS
    W050100.BIO
    VIEW.EXE
    PCMCIA.SYS
    W050101.BIO
    VIEWDOC.EXE
    PMDD.SYS
    W060100.BIO
    HPFS.IFS
    POINTDD.SYS
    W0F0000.BIO
    PMCONTRL.INF
    PRINT02.SYS
    CHKDSK.COM
    OS2.INI
    SCREEN02.SYS
    KEYBOARD.DCP
    OS2SYS.INI
    TESTCFG.SYS
    VIOTBL.DCP
    IBMINT13.I13
    VDISK.SYS
    OS2ASPI.DMD

    Any files removed from this directory can be moved to a Server directory.
    This directory should be placed in the PATH statement of the CONFIG.SYS
    file in the root directory. It would also be wise to create a diskette with
    system utilities such as FORMAT, XCOPY, and the like that will be near the
    requester machine in case the server is not available and maintenance is
    needed on the requester machine.

 2. \OS2\DLL

    Following are the DLL files that are MUST REMAIN in the \OS2\DLL
    sub-directory. This sub-directory will also contain files used for Fonts
    and printer drivers. These files should remain on your requester machine,
    but are not listed here. They have file extensions extensions of PSF, FON,
    DRV, PDR and QPR. This list does not include any DLL files that may be
    placed in the \OS2\DLL sub-directory by another installed product other the
    the base OS/2 system.

    BKSCALLS.DLL
    NAMPIPES.DLL
    PMVIOP.DLL
    BMSCALLS.DLL
    NLS.DLL
    PMWIN.DLL
    BVH8514A..DLL
    NPXEMLTR.DLL
    PMWP.DLL
    BVHVGA.DLL
    NWIAPI.DLL
    PMWPMRI.DLL
    BVHWNDW.DLL
    OS2CHAR.DLL
    QUECALLS.DLL
    BVSCALLS.DLL
    OS2SM.DLL
    REXXINIT.DLL
    DISPLAY.DLL
    PMATM.DLL
    SESMGR.DLL
    DOSCALL1.DLL
    PMCTLS.DLL
    SOM.DLL
    FKA.DLL
    PMDRAG.DLL
    SPL1B.DLL
    HELPMGR.DLL
    PMGPI.DLL
    VIOCALLS.DLL
    HPMGRMRI.DLL
    PMGRE.DLL
    WCFGMRI.DLL
    IBM8514.DLL
    PMMLE.DLL
    WINCFG.DLL
    IMP.DLL
    PMSDMRI.DLL
    WPCONFIG.DLL
    KBDCALLS.DLL
    PMSHAPI.DLL
    WPCONMRI.DLL
    MINXMRI.DLL
    PMSHAPIM.DLL
    WPPRINT.DLL
    MOUCALLS.DLL
    PMSHLTKT.DLL
    WPPRTMRI.DLL
    MSG.DLL
    PMSPL.DLL

    The BVH and IBM DLL files will vary in name depending upon the type of
    display adapter your are using in your system. The rule is, if the name of
    the DLL starts with BVH or IBM, it must remain in the DLL sub-directory on
    the requester machine.

 3. \OS2\MDOS

    Here are the files which SHOULD REMAIN in the \OS2\MDOS sub-directory. The
    APPEND.EXE file is required to be in this sub-directory and cannot be
    moved. The DOSKRNL and COMMAND.COM files are also searched for in this
    directory specifically. All the other files are device driver support.
    These can be removed or may not appear if the devices are not on your
    system, or because of the install options that were used.

    DOSKRNL
    VCDROM.SYS
    VLPT.SYS
    COMMAND.COM
    VCGA.SYS
    VMONO.SYS
    APPEND.EXE
    VCMOS.SYS
    VMOUSE.SYS
    ANSI.SYS
    VCOM.SYS
    VNPX.SYS
    COMDD.SYS
    VDMA.SYS
    VPCMCIA.SYS
    EGA.SYS
    VDPMI.SYS
    VPIC.SYS
    EMM386.SYS
    VDPX.SYS
    VSVGA.SYS
    FSFILTER.SYS
    VDSK.SYS br VTIMER.SYS
    HIMEM.SYS
    VEGA.SYS
    VVGA.SYS
    LPTDD.SYS
    VEMM.SYS
    VWIN.SYS
    V8514A.SYS
    VFLPY.SYS
    VXGA.SYS
    VAPM.SYS
    VKBD.SYS
    VXMS.SYS
    VBIOS.SYS

 4. \OS2\BOOK and \OS2\HELP

    All of the base files in \OS2\BOOK and \OS2\HELP sub-directories CAN BE
    MOVED moved to a server machine. If done, the SET HELP, SET GLOSSARY, and
    SET BOOKSHELF statements in CONFIG.SYS must be updated to point to the
    Server path.

 5. \OS2\SYSTEM

    No files should be removed from this sub-directory.

 6. \OS2\INSTALL

    Different files will be removed from this sub-directory depending on what
    other support is being installed on your system and if service updates are
    going to be applied to the system. Because of service requirements, all
    files except the following should remain in this sub- directory. These
    files CAN BE MOVED.

    DATABASE.DAT
    PRDESC.LST
    SAMPLE.RSP
    DATABASE.TXT
    PRDRV.LST
    USER.RSP
    INSTAID.LIB

    From these files, you may have DATABASE.DAT remain in the \OS2\INSTALL
    sub-directory because it is the MIGRATE Application utility.

 7. \OS2\APPS

    These files were discussed in an earlier append in this document.
    Basically, all of the files can be moved to a server machine, you just have
    to insure that the Productivity and Games icons reflect the correct path
    names.

 8. \OS2\BITMAP

    The only file required in this sub-directory is OS2LOGO.BMP.

 9. \OS2\DRIVERS

    All files in this directory remain there.