DriveSpace Real-Mode Driver May Not Be Removed from Memory

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This article was previously published under Q134364

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SYMPTOMS

The real-mode memory (conventional or upper) used by DriveSpace (Drvspace.bin or Dblspace.bin) may not be reclaimed when you start Windows. This may cause problems with MS-DOS-based programs that require more conventional memory than is available.

Normally, Drvspace.bin (or Dblspace.bin) is unloaded from memory when the 32-bit DriveSpace driver (Drvspacx.vxd) is initialized at Windows 95 startup.

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CAUSE

This problem can occur for any of the following reasons:

You booted to a command prompt, then started Windows by typing "win." The real-mode memory used by Drvspace.bin (or Dblspace.bin) cannot be reclaimed if you interrupt the normal Windows boot process.
You loaded Drvspace.bin (or Dblspace.bin) in upper memory using the following line:
devicehigh=<path>\drvspace.sys /move
The real-mode memory used by Drvspace.bin (or Dblspace.bin) cannot be reclaimed if it is loaded into an upper memory block (UMB).
LoadTop=0 appears in the Msdos.sys file.

A setting of 0 does not let Windows load Drvspace.bin (or Dblspace.bin) at the top of conventional memory (just below 640K). This prevents the unloading of Drvspace.bin (or Dblspace.bin) at Windows startup.

The 32-bit DriveSpace driver (Drvspacx.vxd) is not loaded.

To determine if Drvspacx.vxd is loaded, run DriveSpace, then click About DriveSpace on the Help menu. The following table lists by product the compression driver filenames, sizes, and versions as reported in DriveSpace. "Dblspace.bin" can be substituted for "Drvspace.bin" in this table.

 
      Filename       Product      File Size   About DriveSpace
      ------------------------------------------------------------------
      Drvspace.bin   Windows 95   71,287      Real-mode driver version 2
      Drvspace.bin   MS Plus!     64,135      Real-mode driver version 3
      Drvspacx.vxd   Windows 95   54,207      32-bit driver version 2
      Drvspacx.vxd   MS Plus!     61,719      32-bit driver version 3
      Drvspace.bin   Windows 98   68,871      Real-mode driver
      Drvspacx.vxd   Windows 98   57,642      32-bit driver

Dblspace.bin remains in memory if you are using a configuration consisting of Drvspace.ini and Dblspace.bin. In this configuration, the Dblspace.bin file is loaded as an installable device driver and is not transitioned to Drvspacx.vxd. If you use both Dblspace.bin and Drvspace.bin with Drvspace.ini, Drvspace.bin is given priority and this behavior does not occur.

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RESOLUTION

To resolve this problem, use one or more of the following methods:

Start Windows normally (do not boot to a command prompt, then start Windows by typing "win").
Change the command in the Config.sys file from
devicehigh=<path>\drvspace.sys /move
to:
device=<path>\drvspace.sys /move
NOTE: The syntax of this command is different if you use a third-party memory manager (such as Qualitas 386MAX or QuarterDeck QEMM).
Remove LoadTop=0 from the Msdos.sys file. For information about editing the Msdos.sys file, please see the following article in the Microsoft Knowledge Base:
ARTICLE-ID: 118579 (http://support.microsoft.com/kb/118579/EN-US/ )
TITLE : Contents of the Windows Msdos.sys File
Rename the Drvspacx.vxd file in the Windows\System\Iosubsys folder and then use the procedure below that applies to your configuration:
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If Microsoft Plus! for Windows 95 Is Not Installed
1. Run Windows 95 Setup again.
2. Choose "Restore Windows files that are changed or corrupted" when you are prompted.
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If Microsoft Plus! for Windows 95 Is Installed
1. Click the Start button, point to Settings, and then click Control Panel.
2. Double-click the Add/Remove Programs icon.
3. On the Install/Uninstall tab, click Microsoft Plus! For Windows 95, and then click Add/Remove.
4. When Setup begins, click Reinstall.
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Manually Extract Drvspacx.vxd from the Original Disks or CD-ROM
Manually extract the Drvspacx.vxd file from the original Windows or Plus! disks or CD-ROM. If Plus! is installed, be sure to extract the Drvspacx.vxd file from the Plus! disks or CD-ROM, not from the Windows 95 disks or CD-ROM.

For more information about the Extract tool, type "extract" (without quotation marks) at a command prompt, or see the following article in the Microsoft Knowledge Base:
ARTICLE-ID: 129605 (http://support.microsoft.com/kb/129605/EN-US/ )
TITLE : How to Extract Original Compressed Windows Files
NOTE: The Drvspacx.vxd file for Windows 95 is located in the Win95_09.cab file on disk 9 of the original disks, or in the Win95_09.cab file on the CD-ROM.

The Drvspace.bin file for Windows 98 is located in the Precopy1.cab file. The Drvspacx.vxd file for Windows 98 is located in the Win98_47.cab file.

The Drvspacx.vxd file for Plus! is located in the Plus_1.cab file on disk 1 of the original disks, or in the Plus_1.cab file on the CD-ROM.

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MORE INFORMATION

The real-mode DriveSpace driver (Drvspace.bin or Dblspace.bin) is normally unloaded from memory when the 32-bit DriveSpace driver (Drvspacx.vxd) is initialized at Windows startup. This frees conventional memory for running MS-DOS-based programs.

The real-mode DriveSpace driver is required for accessing compressed drives when Windows is not running. If you have an MS-DOS-based program that requires MS-DOS mode, you may need to do one of the following:

Optimize conventional memory.

NOTE: As stated above, Windows cannot unload the real-mode Drive- Space driver if it is loaded into upper memory.
Create a special startup floppy disk. You can then use that disk to start your computer without DriveSpace, and then run your program from your uncompressed drive.

For more information about this procedure, see the "Freeing Conventional Memory for Running MS-DOS Programs" section of the Microsoft Plus! Readme file for DriveSpace and Compression Agent (Drvspace.txt).

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