KnowledgeBase Archive

An Archive of Early Microsoft KnowledgeBase Articles

View on GitHub

Q106266: System Slows After 32-Bit File Access Is Enabled

Article: Q106266
Product(s): Microsoft Windows 3.x Retail Product
Version(s): WINDOWS:3.11
Operating System(s): 
Keyword(s): 
Last Modified: 22-SEP-1999

3.11

WINDOWS

kbtool kbtshoot kbfile

-------------------------------------------------------------------------------
The information in this article applies to:

- Microsoft Windows for Workgroups version 3.11 
-------------------------------------------------------------------------------

SYMPTOMS
========

Your system seems slower after you enable 32-bit file access.

CAUSE
=====

Enabling 32-bit file access can result in slower system performance in the
following situations:

- VFAT is unable to mount.

  This can happen as a result of one or more of the following problems (note
  that the numbers below correspond to the numbered steps in the "VFAT is
  Unable to Mount" subsection of this article):
  1. The real-mode network redirector has been loaded into memory.

  2. A memory-resident program or device driver has a file open while Windows
     loads.

  3. The drive is involved in a SUBST, ASSIGN, or JOIN action. Because of the
     way they alter apparent disk characteristics, the SUBST.EXE, ASSIGN.COM,
     and JOIN.EXE programs are not compatible with installable file systems
     (IFS), such as 32-bit file access. These utilities can't be used if 32-bit
     file access is enabled.

  4. The cache size selected is too large or invalid.

  5. Required components are missing, corrupted, or not in the specified
     directory.

- Windows for Workgroups version 3.11 is in a low-memory situation after
  enabling VFAT.

  Running VFAT/VCACHE with SMARTDrive may place Windows for Workgroups into a
  low-memory situation because memory used by SMARTDrive is not available to
  VCACHE.386 and vice-versa. Since VCACHE.386 provides the caching on
  VFAT-enabled drives and network drives, while SMARTDrive caches CD-ROM drives
  and floppy disk drives, it is possible that systems with too large a
  percentage of memory allocated to caching have some performance reduction.

WORKAROUND
==========

Low-Memory Situation
--------------------

If you are in a low-memory situation (that is, you are running both SMARTDrive
and VFAT), make sure that the amount of memory allocated to SMARTDrive's
WinCacheSize and the cache size allocated to VCACHE.386 do not exceed roughly 30
percent of total system RAM.

For example, on a machine with 4 megabytes (MB) RAM, if you have allocated 1024
kilobytes (K) to VCACHE, set the SMARTDrive WinCacheSize to 128K. To do this,
use a command similar to the following

  c:\windows\smartdrv.exe <1024> <128>

where <1024> is the InitCacheSize (the cache size at MS-DOS) and
<128> is the size of the cache in Windows.

VFAT Is Unable to Mount
-----------------------

If VFAT is unable to mount, try the following:

1. You can unload the real-mode network redirector by typing "net stop" (without
  the quotation marks) at the MS-DOS command prompt before starting Windows for
  Workgroups.

2. To ensure that no device driver or terminate-and-stay-resident (TSR) program
  has any files open upon entering Windows for Workgroups, clean start the
  machine.

  For more information on clean start configurations for Windows for Workgroups
  version 3.11, query on the following words in the Microsoft Knowledge Base:

  wfw and clean and start

3. Do not use the SUBST, ASSIGN, or JOIN utilities with 32-bit file access
  enabled. If you must use one of these utilities, disable 32-bit access first.

4. Verify that the cache size selected is valid. For more information, see the
  "Low-Memory Situation" section above.

5. The components used by VFAT vary depending on the system's hard disk drive
  (HD) controller type and whether or not disk compression (such as
  DoubleSpace, DriveSpace, or Stac Electronics Stacker) is used. If you suspect
  the components are missing, corrupted, or not in the specified directory,
  verify the components files sizes, or re-expand them from your original
  Windows for Workgroups version 3.11 disks.

  File              Size
  ----              ----
  IOS.386           28,352
  RMM.D32           11,894
  RMM.D32           11,473  (updated version of RMM.D32)
  VCACHE.386         9,862
  VFAT.386          32,925
  VXDLDR.386         5,678

  NOTE: VFAT cannot load on a volume compressed with MS-DOS 6.0 DoubleSpace.
  This problem was resolved in MS-DOS 6.2 and later.

  IMPORTANT: The SYSTEM.INI file entries shown in the examples below are made by
  Control Panel and do not require manual editing. These examples are provided
  to show the component files involved and to aid in troubleshooting. You
  should avoid manually editing your SYSTEM.INI file.

  Example 1: Uncompressed WD 1003 Compatible Drive

  Western Digital 1003 or ST506 compatible drives without compression require
  the following entries in the [386Enh] section of the SYSTEM.INI file:

        [386Enh]
        device=*BLOCKDEV
        device=*PAGEFILE
        device=*int13
        device=*wdctrl
        device=vcache.386
        device=vfat.386

  All entries marked with an asterisk (*) are contained in the WIN386.EXE file.
  All files should be located in your Windows SYSTEM subdirectory unless
  otherwise noted.

  Example 2: Compressed or Not WD 1003-Compatible Drive

  If the drive is compressed, or if another hard disk in the machine is not WD
  1003 compatible, then the line "device=*BLOCKDEV" should be replaced with the
  following:

        device=IOS.386
        device=VXDLDR.386.

  In addition, the real mode mapper (RMM.D32) must exist in the Windows SYSTEM
  subdirectory.

  Example 3: Not WD 1003-Compatible Drive

  If 32-bit disk access cannot be used by a particular hard disk controller
  (because it is not WD 1003 compatible), the VFAT entries for the SYSTEM.INI
  file's [386Enh] section should include the following:

        [386Enh]
        device=*PAGEFILE
        device=vcache.386
        device=vfat.386
        device=IOS.386
        device=VXDLDR.386

  Again, RMM.D32 must exist in the Windows SYSTEM directory.

MORE INFORMATION
================

VFAT is a 32-bit virtual MS-DOS file allocation table (FAT) file system and can
only mount on hard disk volumes. If 32-bit disk access drivers are not available
for a particular hard disk controller, additional handling of INT 13h calls is
required. The IOS.386, VXDLDR.386, and RMM.D32 files provide this functionality
and allow VFAT/VCACHE to work on these drives. (Drives affected include most
SCSI and ESDI drives, a few IDE drives, and compressed volumes residing on any
type of hard disk.)

32-bit disk access drivers may also be provided by an original equipment
manufacturer (OEM) to work with a specific hard disk controller, replacing
Microsoft's *WDCTRL. As a troubleshooting step, these drivers should be
temporarily disabled and IOS.386, VXDLDR.386, and RMM.D32 should be used
instead.

Additional query words: dblspace wfw wfwg 3.11 fastdisk slow slower slows tshoot

======================================================================
Keywords          :  
Technology        : kbAudDeveloper kbWFWSearch kbWFW311
Version           : WINDOWS:3.11

=============================================================================

THE INFORMATION PROVIDED IN THE MICROSOFT KNOWLEDGE BASE IS PROVIDED "AS IS" WITHOUT WARRANTY OF ANY KIND. MICROSOFT DISCLAIMS ALL WARRANTIES, EITHER EXPRESS OR IMPLIED, INCLUDING THE WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. IN NO EVENT SHALL MICROSOFT CORPORATION OR ITS SUPPLIERS BE LIABLE FOR ANY DAMAGES WHATSOEVER INCLUDING DIRECT, INDIRECT, INCIDENTAL, CONSEQUENTIAL, LOSS OF BUSINESS PROFITS OR SPECIAL DAMAGES, EVEN IF MICROSOFT CORPORATION OR ITS SUPPLIERS HAVE BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES. SOME STATES DO NOT ALLOW THE EXCLUSION OR LIMITATION OF LIABILITY FOR CONSEQUENTIAL OR INCIDENTAL DAMAGES SO THE FOREGOING LIMITATION MAY NOT APPLY.