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- ID:VD MS RAMDRIVE, VDISK and QEXT.SYS
- Quarterdeck Technical Note
- by Stan Young
-
-
- DESQview's QEXT.SYS driver for 286 machines with extended memory,
- utilizes 64K of extended memory at the 1 Megabyte address (1024K)
- for loading parts of DESQview outside of the 640K address space.
- Since this lowers the overhead of DESQview in DOS, it is
- generally desirable to load this driver if you have extended
- memory.
-
- QEXT.SYS is compatible with all known versions of IBM's VDISK
- utility and most versions of MS-DOS VDISK. It is not compatible
- compatible with Microsoft's RAMDRIVE.SYS versions prior to 2.00.
- Prior versions of the RAMDRIVE utility are not compatible with
- IBM VDISK or VDISK-type utilities. Since QEXT.SYS must follow
- the VDISK's conventions for loading into memory, RAMDRIVE
- versions prior to 2.00 cannot be used.
-
- It is apparent that some versions of MS-DOS VDISK are actually
- Microsoft RAMDRIVE renamed. QEXT.SYS will not work with these
- either.
-
- If you are having trouble getting QEXT and VDISK to co-exist with
- an MS-DOS version you believe to include a true VDISK, check to
- see if the VDISK reports a version number on boot up that is
- different than the version of DOS you are running. QEXT
- identifies itself by adopting the same version number as the DOS
- that it is running with. This is the IBM convention. If your
- VDISK version is different than the DOS version, QEXT may not be
- identified by the VDISK you are loading. If you think this is
- happening, you might try the version of QEXT.SYS that is
- currently on the DESQview Bulletin Board System. This version
- supports a parameter (/VD) that allows you to specify the VDISK
- version number with which QEXT.SYS will identify itself.
-
- If you are experiencing conflicts between QEXT.SYS, RAMDRIVE.SYS
- or VDISK.SYS, the only solution is to run IBM VDISK, a compatible
- version of MS-DOS VDISK, RAMDRIVE.SYS ver 2.00 or later, or a
- third party RAMDISK utility such as AST's FASTDISK. If you do
- use the AST FASTDISK, be aware that you must specify when loading
- it the address where it should load, since its default is to load
- at 1024K (1 Meg) and if loaded there will disable QEXT.SYS.
- Consult the AST manual for loading instructions. For expanded
- memory users, Compuserve or the DESQview bulletin board contain a
- Shareware program called NJRAMD.SYS that creates a RAMDISK in
- expanded memory. Many users have reported this works well for
- them.
-
- Copyright (C) 1990 by Quarterdeck Office Systems
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