Microsoft KB Archive/135485

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Windows 95 CD-ROM Msdosdrv.txt File (2 of 2)

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Q135485

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The information in this article applies to:


 * Microsoft Windows 95

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SUMMARY
This article contains a partial copy of the information in the Msdosdrv.txt file from the Windows 95 CD-ROM. This article is the second of two articles.

MORE INFORMATION
-- Microsoft Windows 95 README for MS-DOS Device Drivers August 1995 --

(c) Copyright Microsoft Corporation, 1995

This document provides complementary or late-breaking information to supplement the Microsoft Windows 95 documentation.

DBLBUFF.SYS -- Double Buffering

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Loads the Dblbuff.sys device driver to perform double buffering. Double buffering provides compatibility for certain hard-disk controllers that cannot work with memory provided by EMM386 or Windows running in 386 Enhanced mode.

If Windows Setup determined that your system may need double- buffering, it will add a DoubleBuffer=1 entry to the [Options] section of Msdos.sys, which will automatically load Dblbuff.sys. To manually enable double-buffering, you can either add the above entry to Msdos.sys, or add a DEVICE command in your CONFIG.SYS file.

Syntax

DEVICE=[drive:][path]DBLBUFF.SYS [/D+]

Parameters

[drive:][path] Specifies the location of the Dblbuff.sys file.

/D+ Instructs Dblbuff.sys to double-buffer all disk I/O all the time. By default, it will only double-buffer I/O to UMBs, and it will automatically stop double-buffering if it appears to be  unnecessary.

DISPLAY.SYS

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Enables you to display international character sets on EGA, VGA, and LCD monitors. This device driver must be loaded by a DEVICE or DEVICEHIGH command in your CONFIG.SYS file.

Syntax

DEVICE=[drive:][path]DISPLAY.SYS CON[:]=(type[,[hwcp][,n]])

DEVICE=[drive:][path]DISPLAY.SYS CON[:]=(type[,[hwcp][,(n,m)]])

Parameters

[drive:][path] Specifies the location of the DISPLAY.SYS file.

type Specifies the display adapter in use. Valid values include EGA and LCD. The EGA value supports both EGA and VGA display adapters. If  you omit the type parameter, DISPLAY.SYS checks the hardware to   determine which display adapter is in use. You can also specify CGA and MONO as values for type, but they have no effect because character-set switching is not enabled for these devices.

hwcp Specifies the number of the character set that your hardware supports. The following list shows the character sets that MS-DOS supports and the country or language for each:

437   United States 850   Multilingual (Latin I)     852    Slavic (Latin II) 860   Portuguese 863   Canadian-French 865   Nordic

Additional character sets are supported by the EGA2.CPI and EGA3.CPI files.

n Specifies the number of character sets the hardware can support in  addition to the primary character set specified for the hwcp parameter. Valid values for n are in the range 0 through 6. This value depends on your hardware. For EGA display adapters, the maximum value for n  is 6; for LCD display adapters, the maximum value for n is 1.

m Specifies the number of subfonts the hardware supports for each code page. The default value is 2 if type is EGA, and 1 if type is  LCD.

DRVSPACE.SYS, DBLSPACE.SYS

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Determines the final memory location of DRVSPACE.BIN or DBLSPACE.BIN, the part of MS-DOS that provides access to your compressed drives.

DxxSPACE.SYS loads the real-mode driver into upper memory blocks. This can save 60K of conventional memory when you run Windows 95 in real mode, and can save 100K or more if you use Microsoft Plus! for Windows.

When you start your computer, Windows loads DRVSPACE.BIN or DBLSPACE.BIN along with other operating-system functions, before carrying out the commands in your CONFIG.SYS and AUTOEXEC.BAT files. DxxSPACE.BIN initially loads in conventional memory because it loads before device drivers that provide access to upper memory.

When you use DriveSpace or DoubleSpace to create a compressed drive on your computer, the program adds a command for DxxSPACE.SYS to your CONFIG.SYS file.

In the following syntax, for DxxSPACE type the filename for the program you are using.

Syntax

DEVICE=[drive:][path]DxxSPACE.SYS /MOVE [/NOHMA] [/LOW]

DEVICEHIGH=[drive:][path]DxxSPACE.SYS /MOVE [/NOHMA] [/LOW]

Switches

/MOVE Moves DxxSPACE.BIN to its final location in memory.

Initially, DxxSPACE.BIN loads at the top of conventional memory. After Windows finishes carrying out the commands in the CONFIG.SYS file, it moves DxxSPACE.BIN to the bottom of conventional memory. When DxxSPACE.SYS is loaded by using the DEVICE command, it moves DxxSPACE.BIN from the top of conventional memory to the bottom. This can be useful for avoiding conflicts with programs that are loaded from the CONFIG.SYS file and require access to the top of  conventional memory.

When DxxSPACE.SYS is loaded by using the DEVICEHIGH command, DxxSPACE.BIN moves to upper memory, if available. Moving DxxSPACE.BIN to upper memory makes more conventional memory available.

/NOHMA Prevents DxxSPACE.SYS from moving a portion of DxxSPACE.BIN to the high memory area (HMA).

If MS-DOS is loaded into the HMA, DxxSPACE.SYS moves a portion of   DxxSPACE.BIN to the HMA (if there is enough room in the HMA). Use this switch if you do not want DxxSPACE.BIN to use the HMA.

/LOW Prevents DxxSPACE.SYS from loading at the top of conventional memory. Use this switch if you have an MS-DOS-based program that does not support DriveSpace or DoubleSpace at the top of  conventional memory. Note that use of this switch will prevent Windows from reusing the memory occupied by DxxSPACE.sys.

Parameter

[drive:][path] Specifies the location of the DxxSPACE.SYS file.

EGA.SYS

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Saves and restores the display when the MS-DOS Shell Task Swapper is used with EGA monitors. If you have an EGA monitor, you must install the EGA.SYS device driver before using Task Swapper. This device driver must be loadedby a DEVICE or DEVICEHIGH command in your CONFIG.SYS file.

Syntax

DEVICE=[drive:][path]EGA.SYS

Parameters

[drive:][path] Specifies the location of the EGA.SYS file.

EMM386.EXE

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Provides access to the upper memory area and uses extended memory to simulate expanded memory. This device driver must be loaded by a DEVICE command in your CONFIG.SYS file and can be used only on computers with an 80386 or higher processor.

EMM386 uses extended memory to simulate expanded memory for programs that can use expanded memory. EMM386 also makes it possible to load programs and device drivers into upper memory blocks (UMBs).

Syntax

DEVICE=[drive:][path]EMM386.EXE [ON|OFF|AUTO] [memory] [MIN=size] [W=ON|W=OFF] [Mx|FRAME=address|/Pmmmm] [Pn=address] [X=mmmm-nnnn] [I=mmmm-nnnn] [B=address] [L=minXMS] [A=altregs] [H=handles] [D=nnn] [RAM=mmmm-nnnn] [NOEMS] [NOVCPI] [HIGHSCAN] [VERBOSE] [WIN=mmmm- nnnn] [NOHI] [ROM=mmmm-nnnn] [NOMOVEXBDA] [ALTBOOT] [NOBACKFILL]

Parameters

[drive:][path] Specifies the location of the EMM386.EXE file.

[ON|OFF|AUTO] Activates the EMM386 device driver (if set to ON), or suspends the EMM386 device driver (if set to OFF), or places the EMM386 device driver in auto mode (if set to AUTO). Auto mode enables expanded- memory support and upper memory block support only when a program calls for it. The default value is ON. Use the EMM386 command to  change this value after EMM386 has started.

memory Specifies the maximum amount of extended memory (in kilobytes) that you want EMM386 to provide as expanded/Virtual Control Program Interface (EMS/VCPI) memory. This amount is in addition to the memory used for UMBs and EMM386 itself. Values for memory are in  the range 64 through the lesser of either 32768 or the amount of   extended memory available when EMM386 is loaded. The default value is the amount of free extended memory. If you specify the NOEMS switch, the default value is 0. EMM386 rounds the value down to the nearest multiple of 16.

Switches

MIN=size Specifies the minimum amount of EMS/VCPI memory (in kilobytes) that EMM386 will provide, if that amount of memory is available. EMM386 reserves this amount of extended memory for use as EMS/VCPI memory when EMM386 is loaded by the DEVICE=EMM386.EXE command in your CONFIG.SYS file. EMM386 may be able to provide additional EMS/VCPI memory (up to the amount specified by the MEMORY parameter) if  sufficient XMS memory is available when a program requests EMS/VCPI memory. Values are in the range 0 through the value specified by  the MEMORY parameter. The default value is 256. If you specify the NOEMS switch, the default value is 0. If the value of MIN is  greater than the value of MEMORY, EMM386 uses the value specified by MIN.

W=ON|W=OFF Enables or disables support for the Weitek co-processor. The default setting is W=OFF.

Mx Specifies the address of the page frame. Valid values for x are in  the range 1 through 14. The following list shows each value and its associated base address in hexadecimal format:

1 => C000h    8 => DC00h 2 => C400h    9 => E000h 3 => C800h   10 => 8000h 4 => CC00h   11 => 8400h 5 => D000h   12 => 8800h 6 => D400h   13 => 8C00h 7 => D800h   14 => 9000h

Values in the range 10 through 14 should be used only on computers that have 512K of memory.

FRAME=address Specifies the page-frame segment base directly. To specify a  specific segment-base address for the page frame, use the FRAME switch, and specify the address you want. Valid values for address are in the ranges 8000h through 9000h and C000h through E000h, in  increments of 400h. To provide expanded memory and disable the page frame, you can specify FRAME=NONE; however, this may cause some programs that require expanded memory to work improperly.

/Pmmmm Specifies the address of the page frame. Valid values for mmmm are in the ranges 8000h through 9000h and C000h through E000h, in  increments of 400h.

Pn=address Specifies the segment address of a specific page, where n is the number of the page you are specifying and address is the segment address you want. Valid values for n are in the range 0 through 255. Valid values for address are in the ranges 8000h through 9C00h and C000h through EC00h, in increments of 400h. The addresses for pages 0 through 3 must be contiguous in order to maintain compatibility with version 3.2 of the Lotus/Intel/Microsoft Expanded Memory Specification (LIM EMS). If you use the Mx switch, the FRAME switch, or the /Pmmmm switch, you cannot specify the addresses for pages 0 through 3 for the /Pmmmm switch.

X=mmmm-nnnn Prevents EMM386 from using a particular range of segment addresses for an EMS page or for UMBs. Valid values for mmmm and nnnn are in  the range A000h through FFFFh and are rounded down to the nearest 4-kilobyte boundary. The X switch takes precedence over the I  switch if the two ranges overlap.

I=mmmm-nnnn Specifies a range of segment addresses to be used (included) for an  EMS page or for UMBs. Valid values for mmmm and nnnn are in the range A000h through FFFFh and are rounded down to the nearest 4- kilobyte boundary. The X switch takes precedence over the I switch if the two ranges overlap.

B=address Specifies the lowest segment address available for EMS "banking" (swapping of 16KB pages). Valid values are in the range 1000h through 4000h. The default value is 4000h.

l=minXMS Ensures that the specified amount (in kilobytes) of extended memory will still be available after EMM386 is loaded. The default value is 0.

A=altregs Specifies how many fast alternate register sets (used for  multitasking) you want to allocate to EMM386. Valid values are in  the range 0 through 254. The default value is 7. Every alternate register set adds about 200 bytes to the size in memory of EMM386.

H=handles Specifies how many handles EMM386 can use. Valid values are in the range 2 through 255. The default value is 64.

D=nnn Specifies how many kilobytes of memory should be reserved for buffered direct memory access (DMA). Discounting floppy disk DMA, this value should reflect the largest DMA transfer that will occur while EMM386 is active. Valid values for nnn are in the range 16 through 256. The default value is 32.

RAM=mmmm-nnnn Specifies a range of segment addresses to be used for UMBs and also enables EMS support. If you do not specify a range, EMM386 uses all available adapter space to create UMBs and a page frame for EMS.

NOEMS Provides access to the upper memory area but prevents access to  expanded memory.

NOVCPI Disables support for VCPI programs. This switch must be used with the NOEMS switch. If you specify the NOVCPI switch without specifying the NOEMS switch, EMM386 does not disable VCPI support. If you specify both switches, EMM386 disregards the MEMORY parameter and the MIN switch. Disabling support for VCPI programs reduces the amount of extended memory allocated.

HIGHSCAN Specifies that EMM386 use an additional check to determine the availablity of upper memory for use as UMBs or EMS windows. On some computers, specifying this switch may have no effect or cause EMM386 to identify upper memory areas as available when they are not. As a result, your computer might stop responding.

VERBOSE Directs EMM386 to display status and error messages while loading. By default, EMM386 displays messages only if it encounters an error condition. You can abbreviate VERBOSE as V. (To display status  messages without adding the VERBOSE switch, press and hold down the   ALT key while EMM386 starts and loads.)

WIN=mmmm-nnnn Reserves a specified range of segment addresses for Windows instead of for EMM386. Valid values for mmmm and nnnn are in the range A000h through FFFFh and are rounded down to the nearest 4-kilobyte boundary. The X switch takes precedence over the WIN switch if the two ranges overlap. The WIN switch takes precedence over the RAM, ROM, and I switches if their ranges overlap.

[NOHI] Prevents EMM386 from loading into the upper memory area. Normally, a portion of EMM386 is loaded into upper memory. Specifying this switch decreases available conventional memory and increases the upper memory area available for UMBs.

[ROM=mmmm-nnnn] Specifies a range of segment addresses that EMM386 uses for shadow RAM--random-access memory used for read-only memory (ROM). Valid values for mmmm and nnnn are in the range A000h through FFFFh and are rounded down to the nearest 4-kilobyte boundary. Specifying this switch may speed up your system if it does not already have shadow RAM.

[NOMOVEXBDA] Prevents EMM386 from moving the extended BIOS data from conventional memory to upper memory.

[ALTBOOT] Specifies that EMM386 use an alternate handler to restart your computer when you press CTRL+ALT+DEL. Use this switch only if your computer stops responding or exhibits other unusual behavior when EMM386 is loaded and you press CTRL+ALT+DEL.

[NOBACKFILL] When EMM386 is configured to provide upper memory blocks (by using  the NOEMS or RAM switches), EMM386 will also automatically backfill conventional memory if there is less than 640k, in order to bring total conventional memory up to 640k. However, because Windows does not support backfilled conventional memory, use the NOBACKFILL switch if your computer has less than 640K of conventional memory.

HIMEM.SYS

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HIMEM is an extended-memory manager--a program that coordinates the use of your computer's extended memory, including the high memory area (HMA), so that no two programs or device drivers use the same memory at the same time.

You install HIMEM by adding a DEVICE command for HIMEM.SYS to your CONFIG.SYS file. The HIMEM.SYS command line must come before any commands that start programs or device drivers that use extended memory; for example, the HIMEM.SYS command line must come before the EMM386.EXE command line.

Syntax

DEVICE=[drive:][path]HIMEM.SYS [/A20CONTROL:ON|OFF] [/CPUCLOCK:ON|OFF][/EISA] [/HMAMIN=m] [/INT15=xxxx] [/MACHINE:xxxx] [/NOABOVE16] [/NOEISA][/NUMHANDLES=n] [/SHADOWRAM:ON|OFF] [/TESTMEM:ON|OFF] [/VERBOSE] [/X]

In most cases, you won't need to specify command-line options. The default values for HIMEM.SYS are designed to work with most hardware.

Parameter

[drive:][path] Specifies the location of the HIMEM.SYS file. HIMEM.SYS should always be located on the same drive that contains your MS-DOS files. If the HIMEM.SYS file is in the root directory of your startup drive, you don't need to include a path. However, you must always include the complete filename (HIMEM.SYS).

Switches

/A20CONTROL:ON|OFF Specifies whether HIMEM is to take control of the A20 line even if  A20 was on when HIMEM was loaded. The A20 handler gives your computer access to the HMA. If you specify /A20CONTROL:OFF, HIMEM takes control of the A20 line only if A20 was off when HIMEM was loaded. The default setting is /A20CONTROL:ON.

/CPUCLOCK:ON|OFF Specifies whether HIMEM is to affect the clock speed of your computer. If your computer's clock speed changes when you install HIMEM, specifying /CPUCLOCK:ON may correct the problem; however, enabling this option slows down HIMEM. The default setting is  /CPUCLOCK:OFF.

/EISA Specifies that HIMEM should allocate all available extended memory. This switch is necessary only on an EISA (Extended Industry  Standard Architecture) computer with more than 16 MB of memory; on   other computers, HIMEM automatically allocates all available extended memory.

/HMAMIN=m Specifies how many kilobytes of memory a program must require for HIMEM to give that program use of the HMA. Only one program can use the HMA at a time; HIMEM allocates the HMA to the first program that meets the memory-use requirements set by this option. You can specify a value from 0 to 63.

Set /HMAMIN to the amount of memory required by the program that uses the most HMA memory.

The /HMAMIN option is not required; the default value is zero. Omitting this option (or setting it to zero) specifies that HIMEM allocate the HMA to the first program that requests it, regardless of how much of the HMA the program is going to use.

The /HMAMIN option has no effect when Windows is running in 386 Enhanced mode.

/INT15=xxxx Allocates the amount of extended memory (in kilobytes) to be  reserved for the Interrupt 15h interface. Some older programs use the Interrupt 15h interface to allocate extended memory rather than using the XMS (eXtended-Memory Specification) method provided by  HIMEM. If you use these programs, you can ensure enough memory is  available to them by setting xxxx to 64 KB larger than the amount required by the program.

You can specify a value from 64 to 65535; however, you cannot specify more memory than your system has available. If you specify a value less than 64, the value becomes 0. The default value is 0.

/MACHINE:xxxx Specifies what type of computer you are using. Usually, HIMEM can detect your computer type successfully; however, there are a few computers that HIMEM cannot detect. On such systems, HIMEM uses the default system type (IBM AT or compatible). You might need to  include the /MACHINE option if your computer is a type that HIMEM cannot detect and if HIMEM does not work properly on your system by  using the default system type.

Currently, systems that require this option include Acer 1100, Wyse, and IBM 7552.

The value for xxxx can be any of the codes or their equivalent numbers listed in the following table.

Code        Number  Computer type --

at          1       IBM AT or 100% compatible

ps2         2       IBM PS/2

ptlcascade  3       Phoenix Cascade BIOS

hpvectra    4       HP Vectra (A & A+)

att6300plus 5       AT&T 6300 Plus

acer1100    6       Acer 1100

toshiba     7       Toshiba 1600 & 1200XE

wyse        8       Wyse 12.5 Mhz 286

tulip       9       Tulip SX

zenith      10      Zenith ZBIOS

at1         11      IBM PC/AT (alternative delay)

at2         12      IBM PC/AT (alternative delay)

css         12      CSS Labs

at3         13      IBM PC/AT (alternative delay)

philips     13      Philips

fasthp      14      HP Vectra

ibm7552     15      IBM 7552 Industrial Computer

bullmicral  16      Bull Micral 60

dell        17      Dell XBIOS

/NOABOVE16 Specifies not to use INT 15h (ax==E801h) Compaq Bigmem support to  scan for extended memory.

/NOEISA Specifies that HIMEM should not do EISA scanning for extended memory.

/NUMHANDLES=n Specifies the maximum number of extended-memory block (EMB) handles that can be used simultaneously. You can specify a value from 1 to  128; the default value is 32. Each additional handle requires an  additional 6 bytes of memory.

The /NUMHANDLES option has no effect when Windows is running in 386 Enhanced mode.

/SHADOWRAM:ON|OFF Specifies whether to disable shadow RAM (SHADOWRAM:OFF) or to leave the ROM code running from RAM (SHADOWRAM:ON).

Some computers make ROM code run faster by "shadowing" it in RAM-- that is, by copying the ROM code into faster RAM memory at startup, which uses some extended memory. On computers that use shadow RAM and have less than 2 MB of RAM, HIMEM usually attempts to disable shadow RAM to recover additional extended memory for Windows to  use. (HIMEM can disable shadow RAM only on certain types of  systems.) When HIMEM disables shadow RAM, the ROM code runs in the slower ROM instead of RAM; therefore, your computer might run slightly slower than it did before.

/TESTMEM:ON|OFF Determines whether HIMEM performs a memory test when your computer starts. By default, HIMEM tests the reliability of your computer's  extended memory each time your computer starts. This test can identify memory that is no longer reliable; unreliable memory can cause system instability or loss of data. HIMEM's memory test is  more thorough than the standard power-up memory test performed by   most computers. To prevent HIMEM from performing the memory test, specify /TESTMEM:OFF. Disabling the memory test will shorten the startup process. (The default setting is /TESTMEM:ON.)

/VERBOSE Directs HIMEM to display status and error messages while loading. By default, HIMEM does not display any messages unless it  encounters an error. You can abbreviate /VERBOSE as /V. (To display  status messages without adding the /VERBOSE switch, press and hold   the ALT key while HIMEM starts and loads.)

/X Specifies not to use INT 15h (ax==E820h), the latest extended memory support API.

RAMDRIVE.SYS

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Uses part of your computer's random-access memory (RAM) to simulate a hard disk drive. This device driver must be loaded by a DEVICE or DEVICEHIGH command in your CONFIG.SYS file.

RAM drives are much faster than hard disk drives because your computer can read information faster from memory than from a hard disk. A RAM drive appears to be a normal hard disk drive; you can use it just as you would any hard disk drive. The most important difference between a real disk drive and a RAM drive is that because it exists only in memory, information on a RAM drive is lost when you turn off or restart your computer. You can set up as many RAM drives as you want, up to the amount of memory your computer has. To do this, add one RAMDRIVE.SYS line to your CONFIG.SYS file for each additional RAM drive you want.

Syntax

DEVICE=[drive:][path]RAMDRIVE.SYS [DiskSize SectorSize [NumEntries]]] [/E | /A]

Parameters

[drive:][path] Specifies the location of the RAMDRIVE.SYS file.

DiskSize Specifies how many kilobytes of memory you want to use for the RAM drive. For example, to create a 640K RAM drive, specify 640. If you don't specify an amount, RAMDrive will create a 64K RAM drive. You can specify a value from 4 to 32767. However, you cannot specify more memory than your system has available.

SectorSize Specifies the disk sector size in bytes. The size can be 128, 256, or 512 bytes. (If you include a SectorSize value, you must also  include a value for DiskSize.)

Generally, you should use the default sector size of 512 bytes.

NumEntries Limits the number of files and directories you can create in the RAM drive's root directory. The limit can be from 2 to 1024 entries; the limit you specify is rounded up to the nearest sector size boundary. If you do not specify a limit, you can create up to  64 entries in the RAM drive's root directory. (If you include a  value for NumEntries, you must also include values for DiskSize and   SectorSize.)

If there is not enough memory to create the RAM drive as specified, RAMDrive will try to create it with a limit of 16 directory entries. This may result in a RAM drive with a different limit from the one you specified.

Switches

/E Creates the RAM drive in extended memory.

For RAMDrive to use extended memory, your system must be configured so that it provides extended memory, and a DEVICE command for the extended-memory manager (such as HIMEM.SYS) must appear in your CONFIG.SYS file before the DEVICE command for RAMDRIVE.SYS. In  general, it is best to create a RAM drive in extended memory if   your system has extended memory.

/A Creates the RAM drive in expanded memory.

For RAMDrive to use expanded memory, your system must be configured so that it provides expanded memory, and the DEVICE command for the expanded-memory manager (such as EMM386, 386MAX, CEMM, or QEMM) must appear in your CONFIG.SYS file before DEVICE command for RAMDRIVE.SYS.

SETVER.EXE

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Loads the MS-DOS version table into memory. This device driver must be loaded by a DEVICE or DEVICEHIGH command in your CONFIG.SYS file.

SETVER.EXE loads into memory the MS-DOS version table, which lists names of programs and the number of the MS-DOS version with which each program is designed to run.

Syntax

DEVICE=[drive:][path]SETVER.EXE

Parameters

[drive:][path] Specifies the location of the SETVER.EXE file. Keywords :

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