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- @@MENU
- Configure Switches:
- You may reconfigure the following areas of the 386|DOS-Extender:
- 1) Swap files
- 2) Conventional memory
- 3) Extended memory
- 4) Interrupt
- 5) System
-
- Reset Switches:
- If you have made changes to the 386|DOS-Extender switches, you can
- reset these switches to their original settings by selecting Reset
- Switches from the Main menu.
-
- Exit:
- 1) End: Save current switch settings that you have changed and
- exit the program.
-
- 2) Quit: Exit program without saving any changes.
-
- 3) Resume: Return to the Main menu.
-
- ^x70ESC^n key will cancel you out of an option without saving the changes
- you have made.
- @@PRIVEC
-
-
- The IBM BIOS uses INT 5 as the print screen function call. In protected
- mode, INT 5 is treated as a BOUND exception by 386|DOS-Extender.
-
- By default, 386|DOS-Extender makes the BIOS print screen function
- available in protected mode by issuing an INT 80h. The ^x70privec^n switch
- selects a different interrupt vector, in the range 30h - FFh. The switch
- ^x70privec 5^n can be used to tell 386|DOS-Extender not to make the BIOS
- print screen function available in protected mode.
-
- NOTE: We recommend that you do not set ^x70privec^n.
- @@MINREAL
-
-
- The ^x70minreal^n and ^x70maxreal^n switches are used to control how much
- conventional memory is left free by 386|DOS-Extender. By default,
- 386|DOS-Extender allocates all the available conventional memory for
- use by AutoCAD.
-
- If you are using an ADI display driver that requires conventional memory
- from AutoCAD, you must make sure that 386|DOS-Extender leaves sufficient
- conventional memory free. The ^x70minreal^n switch specifies the minimum
- amount of conventional memory to leave free; 386|DOS-Extender refuses to
- run the program if it cannot leave at least this amount of memory free.
- The ^x70maxreal^n switch specifies the maximum amount of conventional memory
- to leave free. 386|DOS-Extender guarantees that at least minreal memory
- is left free and that as much as possible, up to maxreal memory, is left
- free.
-
- Both ^x70minreal^n and ^x70maxreal^n switches take a number as an argument.
- The number specifies memory size in units of 16-byte paragraphs
- (the standard unit of memory allocation under MS-DOS). The number must
- be less than or equal to 65535 (FFFFh). By default, 386|DOS-Extender
- sets both ^x70minreal^n and ^x70maxreal^n to zero.
-
- You can choose to set only the ^x70maxreal^n switch, in which case
- 386|DOS-Extender frees as much conventional memory as possible, up to
- the ^x70maxreal^n amount, but AutoCAD can still run with less than that
- amount. Alternatively, if you set both the ^x70minreal^n and ^x70maxreal^n
- switches, you'll know when there is not sufficient conventional memory
- for the ADI driver because AutoCAD will not run.
-
- NOTE: We recommend that you do not set ^x70minreal^n and ^x70maxreal^n unless
- you need conventional memory beyond what is needed to load your
- TSR and real-mode ADI applications prior to executing AutoCAD.
- @@EXTLOW
-
-
- The ^x70extlow^n and ^x70exthigh^n switches are used to limit the amount of
- extended memory (memory above one megabyte) that 386|DOS-Extender
- allows AutoCAD to use. By default, all extended memory that is not
- allocated to other programs is available for use by AutoCAD. Other
- programs which may have allocated extended memory include RAM disk
- programs, disk cache programs, and EMS simulators.
-
- Both the ^x70extlow^n and ^x70exthigh^n switches take a number as an argument.
- The number specifies a physical memory address in extended memory.
- By default, 386|DOS-Extender sets ^x70extlow^n to 100000h (one megabyte)
- and ^x70exthigh^n to FFFFFFFFh (four gigabytes). 386|DOS-Extender uses only
- extended memory above the address specified with the ^x70extlow^n switch, or
- memory used by other programs, whichever is higher. Similarly, it uses
- only extended memory below the address specified with the ^x70exthigh^n switch,
- or memory used by other programs, whichever is lower.
-
- Normally, it is not necessary to use the ^x70extlow^n or ^x70exthigh^n switches.
- However, if your system has a program installed that uses extended
- memory and does not use the following standards, it may be necessary to
- use one or both of these switches to prevent 386|DOS-Extender from
- allocating extended memory used by the installed program.
-
- * The VDISK or RAMDRIVE standards for allocating memory from one
- megabyte up, or:
-
- * The INT 15h function 88h BIOS call for allocating extended memory
- from the top of memory down.
-
- NOTE: We recommend that you do not set ^x70extlow^n and ^x70exthigh^n unless
- necessary so that AutoCAD may use as much extended memory as
- possible for optimal speed. By not doing so, ^x70extlow^n defaults
- to 100000h and ^x70exthigh^n to FFFFFFFFh.
- @@INTMAP
-
-
- 386|DOS-Extender needs to know which interrupt vectors are used for
- hardware interrupts. Normally, if the default MS-DOS interrupts are
- not used, 386|DOS-Extender can automatically determine this condition.
- However, if there is a compatibility problem, due to another program
- relocating hardware interrupts IRQ0-7 from their default DOS interrupt
- vectors of 08h-0Fh, the ^x70intmap^n switch can be used to tell 386|DOS-
- Extender where hardware interrupts IRQ0-7 are mapped.
- @@VDISK
-
-
- The ^x70vdisk^n switch is a workaround for compatibility problems with other
- programs which do not correctly follow the VDISK standard for allocating
- extended memory.
-
- If 386|DOS-Extender refuses to run AutoCAD because of inconsistent VDISK
- allocation signatures, this switch can be used to force 386|DOS-Extender
- to run AutoCAD. The larger of the two allocation marks present will be
- used.
-
- Before using this switch, you should check the allocation sizes printed
- out with the error message when 386|DOS-Extender refuses to run AutoCAD.
- If the larger of the two numbers printed out does not seem reasonable,
- it will be necessary to calculate how much extended memory is in use by
- other programs and to use the ^x70extlow^n switch to inform 386|DOS-Extender
- of the correct value.
- @@A20
-
-
- The ^x70a20^n switch is used to control how address line 20 is enabled or
- disabled. 80386 systems that conform to the IBM PC/AT standard have
- hardware either to allow full 32-bit addressing ("enable ^x70a20^n") or to
- truncate addresses to 20 bits ("disable ^x70a20^n"). When executing in real
- mode, ^x70a20^n is normally disabled for compatibility with programs that
- take advantage of the address space wrap-around occurring at one
- megabyte on 8088/8086 systems. Very few programs rely on this behavior;
- the most common example is copy protection programs.
-
- By default, 386|DOS-Extender enables ^x70a20^n before starting AutoCAD, and
- restores the original ^x70a20^n setting when AutoCAD terminates. The ^x70a20^n
- switch can be used to force 386|DOS-Extender to disable ^x70a20^n each time
- the 80386 is switched to real mode, and to re-enable ^x70a20^n each time the
- 80386 is switched to protected mode. This can be important if,
- for example, a software driver, which can gain control at any time via
- a hardware interrupt, and which relies on one-megabyte addressing
- wrap-around, is installed on your machine.
-
- There is a penalty associated with the ^x70a20^n switch. Depending on the
- hardware in your system, it can take several milliseconds to enable
- or disable ^x70a20^n. Thus, using the ^x70a20^n switch slows down the switch to
- 80386 real mode, then back to protected mode, that occurs whenever there
- is a hardware interrupt or a DOS or BIOS function call.
- @@SAVEREGS
-
- The ^x70saveregs^n switch forces 386|DOS-Extender to preserve the high 16 bits
- of general registers across switches to real mode initiated by software
- interrupts.
-
- Using the ^x70saveregs^n switch protects an application program from real-mode
- code that uses but does not restore the high 16 bits of the general
- registers. This register saving operation is always performed by default
- for INT 21h and INT 15h.
-
- This switch has no effect on mode switches initiated by system calls
- 250Eh, 2510h, or 2511h.
- @@XT
-
-
- The ^x70xt^n switch is used to inform 386|DOS-Extender that it is executing
- on an IBM-compatible PC or PC/XT with a 386 board, such as the Intel
- Inboard/PC, installed. 386|DOS-Extender normally detects such
- configurations automatically, but it may not be able to detect systems
- which do not have the IBM-standard system ID byte in the BIOS.
- If 386|DOS-Extender does not correctly detect a PC environment, this
- switch can be used to allow AutoCAD to execute successfully.
- @@NOPCD
-
-
- The ^x70nopcd^n switch turns off the assertion of the PCD (Page Cache Disable)
- bits for the Weitek or Cyrix memory-mapped coprocessors on 486 or later
- PCs. By default the PCD bits on 486s or higher are asserted. On Compaq
- machines, the PCD bits are NOT asserted to work around a bug on Compaq
- 486/33L machines. This switch can be used to turn off PCD bits on any
- 486 or later PC.
- @@ERRATA17
-
-
- 80386 chip steps B1 and earlier have two chip errata (known as
- "erratum 17" and "erratum 21") that occur only with protected mode
- programs that use the 80387 floating point coprocessor. Both errata
- cause the 386 to stop processing instructions when an 80387 instruction
- is executed under certain conditions and the program appears to hang.
- Neither erratum exists in any 386SX chip or in 386 chip step D0
- (released in the second quarter of 1988) and later.
-
- The ^x70errata17^n switch installs a software workaround for erratum 17,
- but leaves paging enabled (there is no viable software workaround for
- erratum 21 with paging enabled). The ^x70errata17^n switch is only needed
- if 386|VMM is used, and is only effective if a hardware workaround for
- erratum 21 is in place (preventing erratum 17 does no good if erratum 21
- can still occur). Either use chip step D0 or later of the 386 chip, or
- get a hardware piggyback board with a workaround for erratum 21 from
- Intel or other hardware vendors. Some PC motherboards have a hardware
- workaround for erratum 21 designed in; for example, all Compaq 386/20
- PCs have a hardware workaround.
- @@SWAPNAME
-
-
- The ^x70swapname^n switch specifies the swap file name. If this switch is not
- used, as is the default case with AutoCAD, then a DOS temporary (unique)
- file name is used. If the file name specified with the ^x70swapname^n switch
- is already present on the swap device, 386|VMM refuses to run.
- @@SWAPDIR
-
-
- The ^x70swapdir^n switch specifies the device and directory in which to place
- the page swap file. The default location for the swap file is the root
- directory of the device from which the application program was loaded,
- unless the ^x70swapdefdisk^n switch is used, which is how AutoCAD is shipped
- to you. In that case the default location is the root directory of your
- current disk.
-
- This switch is useful for placing the swap file on a device which has
- sufficient free space to allow the swap file to grow as needed.
-
- The directory name specified with this switch must not end with a "\"
- character, as 386|VMM appends a "\" before adding the name of the swap
- file. The swap file is created with a unique file name (using the DOS
- Create Temporary File system call).
- @@SWAPDEFDISK
-
-
- The ^x70swapdefdisk^n switch selects the current default disk drive for the
- swap file (otherwise the default is the disk on which the application is
- located). One function of this switch is to avoid performance degradation
- from paging over a network.
- @@MINSWFSIZE
-
-
- The ^x70minswfsize^n switch creates a minimum-sized swap file. The size is
- specified in bytes. This switch guarantees that a minimum amount of
- swap space is available at startup. The swap file can then grow
- beyond the minimum as required by the program.
-
- NOTE: We recommend setting ^x70minswfsize^n to ^x70400000^n.
- @@MAXSWFSIZE
-
-
- The ^x70maxswfize^n switch is used to limit the maximum disk space that is
- allocated to the swap file. It specifies a size, in bytes, beyond which
- the swap file is never increased. If this switch is not used, the only
- upper bound on swap file size is the amount of free space available on
- the disk.
-
- @@NOPGEXP
-
-
- The ^x70nopgexp^n switch forces 386|VMM not to page out of the .EXP file.
- When used, 386|DOS-Extender reads the entire program into memory at load
- time and places all swapped out pages (including code pages) in the swap
- file. This can be useful if the application is loaded from the network
- server and paging over the network causes performance degradation.
- @@VSCAN
-
-
- The default setting in AutoCAD for the ^x70vscan^n switch is 20000 milliseconds
- or 20 seconds. This is how often the 386|DOS-extender scans the page
- tables to see if swapping will be required. This setting can be adjusted
- to optimize the performance of some digitizers with AutoCAD.
-
- The frequency of the page table scans is only important on systems where
- there is moderate to heavy swapping activity. The more scans per second
- that are conducted allow the VMM driver to make a better choice of which
- pages to swap out.
-
- On certain polling digitizers, frequent scans of the page table make the
- digitizer skip or miss a sample. If you decrease the number of scans per
- second, by setting ^x70vscan^n to a higher number, digitizer performance is
- markedly improved. If you have a polling digitizer and are running on a
- system with a lot of memory, keep ^x70vscan^n at 20,000 (20 seconds) or higher.
-
-
- If your digitizer is not a polling type, set ^x70vscan^n to a lower number,
- for example, 4000 milliseconds (4 seconds).
-
- You may want to test different ^x70vscan^n parameters to achieve an optimal
- balance between digitizer performance and overall AutoCAD performance.
- @@DEMANDLOAD
-
- The ^x70demandload^n switch causes AutoCAD 386 not to initially load into
- memory; instead it is paged in as needed. This reduces load time and
- guarantees that program pages are not read into memory until needed.
- This may actually increase overall program run times on machines with
- a lot of physical memory, due to the overhead of reading the program in
- one 4K page at a time instead of all at once.
-
- This switch only applies to "acad.exe", it makes no difference on
- ADI or ADS programs.
- @@MAXVCPIMEM
-
- The ^x70maxvcpimem^n switch allows you to configure the DOS-Extender's
- acquisition of VCPI-style expanded memory. This allows you to inhibit
- AutoCAD's desire to acquire all the available expanded memory from a VCPI
- manager such as QEMM, 386MAX, or CEMM.
-
- You may need to use this switch in order to ensure that an ADI display
- list driver obtains a specified amount of expanded memory. For example,
- on a 4MB system, if you have an ADI driver that requires 1 MB of
- expanded memory:
-
- 1. Allocate all the extended memory to the VCPI-compatible 386 memory
- manager. This converts all the extended memory to simulated expanded
- memory.
-
- 2. Configure the AutoCAD 386 executable to acquire a maximum of 3MB of
- VCPI memory by setting the ^x70maxvcpimem^n switch to 3,072,000.
-
-
- Now you can run AutoCAD 386 and allow the ADI driver to acquire 1MB of
- memory to store its display list.
-
- By default AutoCAD does not use the ^x70maxvcpimem^n switch.
- If the ^x70maxvcpimem^n switch is not used, 386|DOS-Extender will allocate all
- available EMS memory.
- @@MAXBLKXMS
-
- The ^x70maxblkxms^n switch defines the maximum size, in bytes, of an individual
- XMS block (default = 4 GB). XMS memory, unlike direct extended memory and
- VCPI memory, cannot be released until after the program terminates. This
- switch can be used to cause 386|DOS-Extender to allocate XMS memory in
- smaller chunks, leaving some XMS memory free if the application doesn't
- need it all.
- @@MAXXMSMEM
-
- XMS memory refers to memory allocated through the XMS (eXtended Memory
- Specification) interface, the Microsoft standard for allocation of
- memory above one MB. The XMS interface is usually provided by installing
- a device driver called HIMEM.SYS.
-
- The ^x70maxxmsmem^n switch defines the maximum number of bytes of XMS memory to
- allocate (default = 4 GB).
- @@MAXEXTMEM
-
- The ^x70maxextmem^n switch defines the maximum number of bytes of direct
- extended memory to allocate (default = 4 GB).
-
- This switch can be used instead of ^x70extlow^n and ^x70exthigh^n as a
- means of controlling extended memory usage.
- @@NOSPCL
-
- The ^x70nospcl^n switch disables the automatic use of special memory, such
- as the built-in memory mapped above 14 MB on Compaq 386 machines. By
- default, 386|DOS-Extender attempts to use such memory if it is not
- allocated to another program. This switch instructs 386|DOS-Extender
- not to check for such memory. Normally, it is not necessary to use this
- switch.
- @@VSLEN
-
- The ^x70vslen^n switch specifies the maximum amount of linear address
- space to process on each ^x70vscan^n scan. One might vary this parameter
- to improve digitizer performance by doing less work on each ^x70vscan^n.
- ^x70vslen^n has no effect on Interrupt mode digitizers.
- @@LFU
-
- The ^x70lfu^n switch sets the page replacement policy to Least Frequently
- Used. This is the default page replacement policy.
-
- The ^x70nur^n switch sets the page replacement policy to Not Used Recently.
- @
-