Microsoft Knowledge Base

• Microsoft MS-DOS operating system versions 6.2, 6.22

IMPORTANT: Although the text in the following questions and answers specifically refers to MS-DOS 6.2 DoubleSpace, the information also applies to MS-DOS 6.22 DriveSpace. If you have MS-DOS 6.22, substitute DRVSPACE for any DBLSPACE commands.

1. Q. What new features does MS-DOS 6.2 DoubleSpace include?

   A. Microsoft DoubleSpace has several new features that add an
      increased layer of data protection and ease of use. For example:

      - DoubleSpace installation procedure now calls ScanDisk, a new
        utility that detects, diagnoses, and repairs disk errors on
        uncompressed drives and DoubleSpace-compressed drives.

      - DoubleSpace now includes DoubleGuard safety checking, which
        protects against data corruption by verifying data integrity
        before writing to your disk.

      - DoubleSpace automatically mounts compressed floppy disks and
        other compressed removable media even when Windows is
        running.

      - With MS-DOS 6.2, you can easily uncompress a DoubleSpace
        drive or even completely uninstall DoubleSpace from memory.

      - You can bypass DoubleSpace when you start your computer to
        make troubleshooting easier and also temporarily free memory
        for use by other applications.

      For more information, type "help whatsnew" or "help dblspace"
      (without the quotation marks) at the MS-DOS command prompt and
      then press ENTER.

2. Q. I am currently using a third-party disk-compression software package
      and now want to convert to DoubleSpace. How can I do this?

    A. If you use a third-party disk-compression program, you need to back
       up your program and data files, install MS-DOS 6.2, remove your
       third-party disk-compression software, compress your drives with
       DoubleSpace, and then restore your program and data files.

       For more detailed information, order FastTips Technical Library
       item Q103949, titled "Converting to DoubleSpace from Third-Party
       Disk Compression."

3. Q. I installed DoubleSpace and now each time I enter Microsoft
      Windows I receive the error "Corrupt Swapfile Warning." I have
      set up my permanent swap file many times, but I continue to
      receive this error. How can I correct this problem?

   A. In this case, the error "Corrupt Swapfile Warning" probably
      means your permanent swap file is being created on a DoubleSpace-
      compressed volume. Windows cannot create a permanent swap file
      on a compressed volume. To correct this problem, set the
      permanent swap file to an uncompressed drive, such as your host
      drive.

      Windows cannot detect DoubleSpace-compressed drives because
      Windows' release predates the release of DoubleSpace.

4. Q. Because DoubleSpace has assigned drive F (or higher) for its
      own use, my Novell NetWare logon scripts no longer work. How can I
      correct this problem?

   A. The drive letter F (normally used by Novell NetWare) may be used
      by DoubleSpace. To work around this situation, you can either
      use a different drive letter for your login drive, or adjust
      DoubleSpace so that it uses a different drive letter for its
      host drive.

      If your usual NetWare drive letter is unavailable, use one of
      the following methods to change the DoubleSpace host drive
      letter:

       - Ensure any C:\DOS\DBLSPACE.SYS commands are placed before any
         RAMDRIVE.SYS statements in your CONFIG.SYS file.

         -or-

       - Use the DBLSPACE /HOST command to change the host drive
         letter.

      NOTE: You can usually avoid this problem by making sure your
      NetWare software is loaded before you run DoubleSpace to
      compress your drives.

      For specific instructions to correct this situation, order
      FastTips Technical Library item Q97565, titled "Novell Login
      Drive Not Available After Installing DoubleSpace."

5. Q. I occasionally receive a red full-screen DoubleGuard error
      message and my computer stops responding (hangs). What is
      causing these errors and how can I prevent them?

   A. DoubleGuard ensures your data is safe by verifying data
      integrity before writing data to your disk. If DoubleGuard
      detects that the memory DoubleSpace is using has been corrupted
      by another program, it shuts down your computer immediately to
      minimize damage to your data.

      If you are consistently getting DoubleGuard errors when you run
      a particular application, the application is likely overwriting
      DoubleSpace information in memory. For more information and
      assistance in troubleshooting this problem, contact the
      application software vendor.

      If there is no particular pattern to the DoubleGuard errors, you
      may have a conflict between device drivers and/or terminate-and-
      stay-resident (TSR) programs in your CONFIG.SYS and AUTOEXEC.BAT
      files. For more detailed information on troubleshooting your
      CONFIG.SYS and AUTOEXEC.BAT files, order FastTips Technical
      Library item Q68128, titled "Troubleshooting the CONFIG.SYS and
      AUTOEXEC.BAT Files."