Path: utzoo!utgpu!watmath!att!dptg!rutgers!network!ucsd!nosc!cod!baird
From: baird@cod.NOSC.MIL (John M. Baird)
Newsgroups: comp.sys.ibm.pc
Subject: Re: Can HIMEM.SYS co-exist with VDISK.SYS
Message-ID: <1609@cod.NOSC.MIL>
Date: 15 Aug 89 18:05:36 GMT
References: <-286529991@hpcupt1.HP.COM>
Organization: Naval Ocean Systems Center, San Diego
Lines: 56

From article <-286529991@hpcupt1.HP.COM>, by swh@hpcupt1.HP.COM (Steve Harrold):
> Can HIMEM.SYS co-exist with VDISK.SYS?
> In a nutshell, can HIMEM.SYS and VDISK.SYS co-exist in a 286 machine?

If you have DOS 3.0 or later and the version of HIMEM.SYS that comes with
Windows/286 (or 2.10), or 2.06 HIMEM.SYS direct from Microsoft (they give
it away for free, SIMTEL20 has it), HIMEM.SYS and some RAM disk programs
can co-exist. The one from Microsoft that comes with Windows (RAMDrive)
certainly can. I don't know about VDISK.SYS or some of the popular third
party RAM drivers. Appended is an excerpt from the README.TXT file for
Windows/286 that gives some more information on the topic. If you configure
VDISK so that it leaves 64KB for HIMEM, and install HIMEM first in CONFIG.SYS,
chances are good it will work.

John Baird, Naval Ocean Systems Center, San Diego, CA
       [with annotations in square brackets]
================================================================================
                         MICROSOFT WINDOWS/286 VERSION 2.1
================================================================================
Using SMARTDrive [their cache disk driver]
----------------
Appendix C, "Speeding Up Windows with SMARTDrive" in the Windows User's
Guide contains detailed instructions on installing the disk-caching
program SMARTDrive provided with Windows 2.1. 

Using RAMDrive [their RAM disk driver]
--------------
In general, SMARTDrive gives better overall performance than RAMDrive.
One exception is output performance for frequently written files.  We
recommend that you use SMARTDrive; however, a new version of RAMDrive
is included with Windows 2.1.  

Using HIMEM.SYS on 286 or 386 machines with extended memory
-----------------------------------------------------------
On 286 or 386 machines with extended (NOT expanded) memory, it is
possible to gain between 45Kb and 60Kb of additional conventional
memory.  To gain this memory, the driver, HIMEM.SYS, must be
installed in your CONFIG.SYS file. [before anything that calls it,
like RAMDrive or VDISK.]

If HIMEM.SYS is installed and you do not have at least 64Kb of available
extended memory, it is either because you don't have enough extended
memory mapped to segment FFFE, or because SMARTDRV.SYS or RAMDRIVE.SYS
have already allocated that memory.  

     o  Make sure that RAMDRIVE.SYS and/or SMARTDRV.SYS do not allocate
        all of your extended memory.  At least 64Kb must be reserved for
        HIMEM.SYS.  

     o  If you have an EXPANDED memory card which you plan to use for
        HIMEM.SYS, you must configure the expanded memory hardware such
        that at least 64Kb of the memory on the card will be used as
        EXTENDED memory.  
================================================================================
                               END OF README.TXT
================================================================================