PC World Interactive 1/PC World Interactive 1 - Nisan 1997.iso/nostalji/bbs/modem/fx.arj/README.BOX

Text File | 1989-11-08 | 24KB | 474 lines

            EXPANSION BOX REFERENCE MANUAL

            Published by Rupp Corporation
     Copyright (C) 1989 by Sewell Development Corporation

    Expansion Box is a set of programs that allow one IBM compatible
PC to use the disks and printers of another IBM compatible PC.    This
document describes the various device driver and TSR modules of
Expansion Box.

Note:  Expansion Box and FastLynx are independent programs.  FastLynx
does not require Expansion Box nor does Expansion Box require
FastLynx.  However, it is possible to use FastLynx in "Local Copy"
mode with the Expansion Box device drivers.

    The basic idea behind Expansion Box is to let one PC use another
PC as an expansion box.  The communication between the two PCs is
accomplished with the high speed serial and parallel protocols
developed for FastLynx (Fastwire II).  The FastLynx program transmits
files quickly between two computers.  However, in many environments
it is convenient to use two computers as if they are one computer.
Expansion Box lets the disks and printers of one computer be accessed
directly by another.  Thus application programs can access
information on both computers simultaneously.  Regular DOS commands
can use files on both computers and printing can be done by either
computer (or both).

    A program like Expansion Box is possible because of a powerful
feature of the MS-DOS operating system--known as installable device
drivers.  Device drivers are part of the operating system.  They
perform communication between a device--such as a disk or
printer--and the rest of the computer.    In some cases the device is
in the same box as the rest of the computer (for example a disk or
internal modem).  In other cases the device is separate from the
computer and communication is performed through a communication port
and cable (such as a printer).    In either case, the device driver is
the software that controls the communication to the device.

    Expansion Box device drivers are no different from regular device
drivers.  Communication occurs on a serial or parallel cable and the
controlled device is another computer.    The computer with the device
drivers is called the lead or master computer.    The controlled
computer is called the server or slave computer.

    You may have noted that these device drivers are "installable".
Unfortunately, this means that they must be installed.    The EBOX
program has a quick and easy installation option.  The installation
option modifies your CONFIG.SYS and AUTOEXEC.BAT files.  To start the
installation process, connect both computers with either a serial or
parallel FastLynx cable and start the EBOX program on both computers.
On the lead computer (you must decide which should be the lead
computer) press Enter and follow the given instructions.

    It's likely that you will need no further information about the
installation process.  However, some environments require a different
setup than the installation option provides.  To handle these
situations, an explanation of the device driver options and features
follows.  If you have any problems or suggestions, please give us a
call!



             EXPANSION BOX FILES


There are seven files in the Expansion Box program.  They are:

1) EBOX.EXE    The server program.  Execute this program on the
        server computer when you want Expansion Box to be
        active.  EBOX handles requests from the device
        drivers on the lead computer.  Also, EBOX has options
        to install the device drivers, to change the current
        drive assignments and print mode, and to un-install
        the device drivers.

2) EBOX.HLP    The help screens for the EBOX.EXE program.

3) README.BOX    This file.

4) EBOXPAR.SYS    The main Expansion Box device driver for parallel
        communication.    This device driver contains all the
        code needed to use the disk drives of the server
        computer using a parallel communication protocol.

5) EBOXSER.SYS    The main Expansion Box device driver for serial
        communication.    This device driver contains all code
        needed to use the disk drives of the server
        computer using a serial communication protocol.

6) EBOXCHAR.SYS An auxiliary Expansion Box device driver for
        additional character devices.  This device driver
        contains all the code needed to use character devices
        on the server computer.  Usually this would be a
        printer, but it could also be used for COM ports or
        even the server's clock.

7) EBOXPRN.COM    A TSR (Terminate and Stay Resident) program used for
        redirecting BIOS level printing.

EBOX.EXE and EBOX.HLP are the only files required on the server
computer.  All others are used only on the lead system.  The EBOX.EXE
program must be executing on the server system with the FastLynx
cable connected for the lead system to be able to access the drives
and devices of the server.  If EBOX is not executing or the cable is
not connected, a drive or device not ready error will be issued.



    Main Block Device Drivers EBOXSER.SYS and EBOXPAR.SYS

    EBOXSER.SYS and EBOXPAR.SYS perform the same function.  The only
difference between the two drivers is the communication protocol
used.  EBOXSER.SYS uses serial communication and EBOXPAR.SYS uses
parallel communication.  The installation process will determine
which FastLynx cable you connected and install the correct driver for
that cable.  The installation process also performs three other
important services for these drivers:

    First, it sets the ports on which communication can take place.
It sets the device drivers port list to EBOX's port list.  The
parallel driver ignores serial ports, likewise the serial driver
ignores parallel ports.  Normally the port list is "LPT*,COM*", and
communication can occur on all valid ports.  To have the program
automatically select the port that is connected to the other computer
is a great convenience.  However, you can select a specific or
non-standard port (or set of ports).  See the help screen to the port
list configuration for more details.

    Second, the installation process sets up the default drive
assignments.  Each drive on the server computer that you want to use
from the lead computer must be assigned a drive letter.
Unfortunately, the drive letter on the server system is usually being
used by some other drive on the lead system.  For example:  if you
want to use the server's drive A:, it needs to be assigned a drive
letter on the lead system.  It would be nice to use the same drive
letter, but A: is already assigned to the lead computer's floppy disk
so another drive letter, such as D: or E:, must be assigned.  It is
possible to assign any currently unused letter to the drive. However,
MS-DOS assigns drive letters sequentially.  If you assign a drive to
the letter Z:, all other drive letters (for instance letters between
E: and Y:) will be unavailable for use other than within EBOX.    Also,
each unused drive letter can require up to 200 bytes of resident
memory!  Attempts to use unassigned drive letters will result in the
lead system issuing an invalid unit number error.  The installation
option will display a warning if this condition can occur.

    The drive letter assignments are probably the most difficult part
of the Expansion Box programs to understand and use.  It is often
difficult to remember which drive letters you have assigned to server
drives.  You can examine the current drive assignments by choosing
the "Change drive assignments" option of the EBOX program.  This
option also allows you to change the current drive assignments.

    One mnemonically useful way to set up the drive assignments is
to assign the server systems floppy drive to F: and its hard disk
to H:.

    The last service performed by the installation option is for
serial drivers only.  The installation will set the baud rate of the
serial driver to the baud rate used at installation time.  Some
computers cannot use the highest baud rate (notably the PS-2
Model-80).  If you are having problems with serial communication,
run the FastLynx diagnostic option to determine a safe baud rate.

    There are some options for block device drivers that are not
available through the installation process.  To use these options,
install the device driver normally.  After installing the drivers,
you can edit your CONFIG.SYS file to take advantage of these options.
After you have edited the CONFIG.SYS file, you will need to re-boot
the computer to make the options effective.  The syntax for the
device line in the CONFIG.SYS file is as follows:

    DEVICE=[path\]EBOXPAR.SYS [/Rdddd] [/Ssignature] [/A]

    for parallel communication or

    DEVICE=[path\]EBOXSER.SYS [/Rdddd] [/Ssignature] [/A]

    for serial communication (fields in [] are optional).

    /Rdddd    Specifies a maximum wait time for receive timeouts in
        seconds.

    /Ssignature Specifies a unique signature for this device driver.

    /A        Specifies Auto Configuration Mode.

    Some types of devices are unusually slow in responding to
requests made by the device driver.  Normally the device driver makes
a request and waits for a response from the server system.  The
maximum time that the device driver will wait is specified with the
/R option.  Example: /R60 tells the device driver to wait one minute
before timing out.  The default value is 20 seconds.  This is more
than necessary for all hard disks, floppy disks, ram disks, etc.
However, once in a while a longer timeout is needed.  A case where a
longer timeout would be needed is when a tape drive is being used to
emulate a disk drive and the rewind time takes too long.

    The /S switch is used to give this device driver a unique
identity.  This is useful for hooking up multiple server computers to
one lead computer.  A later section explains the use of this option.

    In some environments it is useful to have the drive assignments
set up according to information received at boot time.    The following
actions will take place when the /A option is used and communication
is established at boot time.  1) The number of logical drives
installed will be the number of logical drives on the server system.
2) The drive assignments will begin at the first available drive
letter and proceed sequentially--one for each drive on the server.
If communication is not established at boot time, the /A option has
no effect.  After booting, the drive assignments can be changed in
the normal manner.  This option is most useful when you are using one
computer to hook up to several different server computers at
different times.  However, its usefulness is limited because you must
reboot every time you hook up to a different computer.    If you do not
reboot when you hook up to another computer, you will receive a
server mismatch error.    Expansion Box forces this error to avoid
problems with the computer's disk cache.



           BIOS Level Print Redirector EBOXPRN.COM

    Printing can be sent to the server computer at two levels.    One
method is to install a character device driver for the printer.  This
method will be described in the next section.  Another method is to
trap the print requests at the BIOS level.  There are several
advantages to trapping print requests at the BIOS level.  First, many
applications use BIOS level printing rather than DOS level printing.
Also, the Print Screen keys (PrtSc and Ctrl/P) use BIOS level
printing.  The standard LPT device drivers simply call the BIOS to
perform the actual printing, so trapping the print requests at the
device driver level is not really necessary.

    The EBOXPRN.COM TSR performs BIOS level print redirection.    The
installation process will place a command in AUTOEXEC.BAT to load
this TSR.  If you do not desire printing to be redirected, remove the
line from AUTOEXEC.BAT.  EBOXPRN requires that one of the Expansion
Box block drivers be loaded.  If a main block driver is not found, an
error message will be displayed and EBOXPRN will not install itself.
If EBOXPRN has already been loaded, it does not reload itself, but
simply changes the current options.  The command line is:

    eboxprn [/Ssignature] [/Mm] [/Pls[ls[ls]]]

    The /Ssignature option identifies a particular main Expansion Box
driver that contains the communication protocol.  This option is
described in a later section.

    The /P switch specifies a port mapping table.  Each ls pair
contains a mapping for a single BIOS port.  Both the l and the s must
be between 1 and 3 inclusive.  The l specifies the line printer
number on the lead system (1 for LPT1, 2 for LPT2, ...) and the s is
the line printer number on the server system to which the print from
the lead printer is to be sent.  If the /P is specified, all ports
not specifically mentioned, will not be redirected.  Examples:

    /P12    redirects lead printer LPT1 to server printer LPT2 and
        does not redirect LPT2 or LPT3.

    /P1222  redirects both LPT1 and LPT2 to the server's LPT2.  LPT3
        is not redirected.

    If no /P switch is found when the TSR is loaded, /P112233 is
assumed.

    The /Mm defines the current printing mode.    M can be one of R, L,
or A.

    R    Remote mode.  When in remote mode, all print requests will be
    sent to the server system.  If the server printer is not on-
    line or the server system is not connected (or not running
    EBOX), a printer off line error code will be returned to the
    lead system.

    L    Local mode.  When in local mode, print requests are not sent
    to the server computer.  No port mappings are done.  This
    mode essentially turns off all print redirection.

    A    Autoswitch mode.  This mode attempts to print on the server
    computer.  However, if the server printer is not on-line,
    an attempt will be made to do the printing on the lead
    computer.  Essentially, this mode attempts to find which
    computer has an on-line printer, and sends the print request
    to that printer.

    The print mode can be changed by either the EBOXPRN command or by
using the Change Print Mode option in the EBOX program.  The port
mapping table can only be changed with the EBOXPRN command.


        Character Device Drivers EBOXCHAR.SYS

    There are two kinds of device drivers--block and character.  Block
devices are devices which have files stored on them--such as disks,
or floppy disks.  Character devices are non-file devices used for
input or output--such as printers, keyboards, or mice.    Accesses to
block devices are made through drive letters such as A: or C:.
Accesses to character devices are made through a name such as COM1 or
LPT2.  The EBOXPAR.SYS and EBOXSER.SYS device drivers are block
drivers.  With one of those device drivers, you can get access to all
of the block devices on the server computer.  EBOXCHAR.SYS is a
character driver with which you can gain access to a single character
driver on the server system.  The installation program does not
install this driver for you.  If you wish to use one of the server
system's character devices, you will need to add the following
DEVICE= line to your CONFIG.SYS file:

    DEVICE=[path\]eboxchar.sys /Nname /Rserver_name [/Ssignature]

    The signature option and path are optional.  However you must
specify both the lead name (/N) and the server name (/R).  These
options are described below:

    The /Ssignature option is used to identify the particular main
Expansion Box driver that contains the communication protocol.    This
will be described in a later section.  Note, an Expansion Box block
device driver must be loaded before any character device drivers.

    The /Nname option specifies the character device name on the lead
system.  This can be from one to eight of the valid filename
characters.  If this name is the same as a device driver that already
exists on the lead system, then the previous driver will be
superceded by this device driver.

    The /Rserver_name specifies the character device name on the
server system.    This device name must be an already existing device
driver on the server system.  If it does not exist, you will be given
an error message if you attempt to use the device.  Like the lead
name, this name can be from one to eight valid filename characters.

    Examples:

    DEVICE=EBOXCHAR.SYS /NLASER /RLPT2

    This device line adds a new device LASER to the lead system.
Output requests made to the device LASER will be sent to the server
system's LPT2.

    DEVICE=EBOXCHAR.SYS /NPRN /RPRN

    This device line replaces the lead systems PRN device with the
remote systems PRN device.  Output that would normally go to the PRN
device on the lead computer will be sent to the PRN device on the
server computer.  Normally this would not be needed as the BIOS level
redirection (EBOXPRN.COM) can perform the same operation.  However,
if you have an improved print spooler, it may be useful to redirect
the print at the device driver level rather than the BIOS level to
take advantage of the spooler's better print buffering.

    DEVICE=EBOXCHAR.SYS /NCOM2 /RCOM1
    DEVICE=EBOXCHAR.SYS /NREMPRN /RPRN

    The above example adds two device drivers to the lead system.
Note that both device drivers use the same driver file.  The first
line replaces the lead system's COM2 with the remote system's COM1
device.  Input and output requests on COM2 will be redirected from/to
the server system's COM1.  The second line adds a new device REMPRN
to the lead computer.  It will send output to the server computer's
PRN device.  (Note, there is a difference between the device PRN and
LPT1--the difference is the name--but DOS thinks that the two are
different devices).

    Any character device driver can be superceded by an Expansion
Box device (except the NUL device).  This includes devices such as
CLOCK$ and CON.  However, overriding the CON device (the keyboard and
screen) will most likely not yield the expected results.  Too many
programs skip the device driver levels and write directly to the
screen or read directly from the keyboard at the BIOS or hardware
level.    If you want to experiment with the CON device we STRONGLY!!
recommend that you test the process from a bootable floppy disk
before installing the device driver on you hard disk!


        Installing More than One Expansion Box

    It is possible to have multiple servers attached to a single lead
computer.  The main block drivers do all of the actual communication.
The character device drivers and the TSR look for the presence of a
main block driver and use the protocol routines within the main
driver for communication to the server computer.  This is done to
save (a lot of) resident memory.  However, it causes problems when
multiple block drivers are installed; an auxiliary driver or TSR will
not know which main driver to use.  To solve this problem all
Expansion Box device drivers, TSRs and the EBOX program itself take a
command line argument /Ssignature.  When the auxiliary driver or TSR
is loaded, it looks for the main driver with the matching signature.
If a main driver with the same signature is not found, an error will
be reported and the device driver will not be installed.  The
signature can be from one to eight valid filename characters.

    To change drive mappings or print modes when multiple drivers are
installed, the EBOX.EXE program also takes a /Ssignature option on
the command line.  Note that if you misspell the signature, the EBOX
program will not find the main driver you were looking for and think
that no drivers are installed.    If this happens, simply exit and try
again.

    One other problem can occur when trying to install multiple
Expansion Boxes.  If you have additional FastLynx parallel or serial
cables, you may want to use the same communication protocol to talk
to both server computers.  The problem is that the device drivers for
both server computers would have the same name (either EBOXSER.SYS or
EBOXPAR.SYS).  The port list and drive assignments tables are part of
the driver itself, so you cannot use the same device driver file for
both servers.  One solution to this problem is to install the first
driver, rename the device driver and change the DEVICE= line in
CONFIG.SYS appropriately, then install the second driver (with a
different port list, signature, and drive assignment tables).  You
should completely install the first driver (including the re-boot)
before attempting to install a second one.


    Partitions Larger than 32MB and 12-bit vs 16-bit FATs

     Expansion Box correctly handles partitions larger that 32MB on
IBM DOS 4.0, Compaq DOS 3.31, and Zenith DOS 3.30 PLUS.  The method
to handle large partitions for DOS 4.0 is slightly different than the
method used by DOS 3.31 and DOS 3.30+.    However, Expansion Box
detects this condition and adjusts accordingly.  That is, it is
possible to have a DOS 4.0 system for one computer and a DOS 3.31 or
DOS 3.30+ system for the other, both with large partitions.

    Due to the evolving nature of MS-DOS, there are certain errors
that can occur when the lead computer is running a DOS version
previous to the DOS version on the server.  These conditions are
given below.  Please note, it is always possible to reverse the roles
of the computers to avoid these problems.

    DOS 2.xx cannot access a DOS 3.xx or 4.xx disk if the FAT (File
Allocation Table) entries are 16-bits.    DOS 2.xx can only access
12-bit FATs.  DOS 3.0 and greater can access both 12-bit and 16-bit
FATs.  Attempts by a lead system running DOS 2.xx to access a server
disk drive that has a 16-bit FAT will result in a NON-DOS disk error
(which can only be aborted).

    DOS versions previous to DOS 3.31 cannot access partitions larger
than 32MB.  An attempt by a lead computer running a DOS version
previous to DOS 3.31 to access a partition larger that 32MB will
result in a NON-DOS disk error.

    There are several products on the market that modify DOS to be
able to access partitions larger than 32MB (previous to DOS 3.31).
To use Expansion Box with these products, both computers must be
running the same modified DOS version.    Attempts to access partitions
larger than 32MB by DOS versions that are not modified in the same
manner will result in a NON-DOS disk error.  Generally these products
work by using a sector size larger than 512 bytes.  Expansion Box
looks for sector size incompatibility and issues errors and warnings
appropriately.

    You can also hook multiple computers up in a chain.  However, the
performance will not be as good as if the server computers are hooked
up directly to the lead.  In this case the computers in the middle of
the chain are acting as both lead and server simultaneously.

           Optional Device Driver Features

    Starting with DOS 3.0 there are several optional features for
device drivers.  The Expansion Box block drivers support all of these
optional features except IOCTL and GENERIC IOCTL (which include get
and set logical device).  Since Generic IOCTL is not supported, you
will not be able to format disks through the Expansion Box drivers.

    The only feature not supported in the Expansion Box character
drivers is GENERIC IOCTL.  Not supporting the Generic IOCTL feature
means that setting alternate character sets for character devices
cannot be done though the Expansion Box.  Note that the normal IOCTL
is support (since it is often used to control printers and modems).

    Also note: attempts to access Expansion Box devices through the
BIOS will not work (except BIOS printing which is handled by
EBOXPRN.COM).