MS-DOS Err Msg with DoubleSpace: Insufficient Disk Space (100911)

The information in this article applies to:
    Microsoft MS-DOS operating system 6.0
    Microsoft MS-DOS operating system 6.2
    Microsoft MS-DOS operating system 6.21
    Microsoft MS-DOS operating system 6.22

This article was previously published under Q100911
This information applies to both Microsoft DoubleSpace and Microsoft DriveSpace. For MS-DOS 6.22, use DRVSPACE in place of DBLSPACE for commands and filenames.


When you copy or create files on a DoubleSpace-compressed drive, it is possible to receive an "Insufficient Disk Space" error message when MS-DOS reports sufficient space to perform the operation. This article discusses potential causes of this problem and workarounds.


There are several instances, including those listed below, in which MS-DOS may report insufficient disk space when copying files to a compressed drive.
    The estimated compression ratio (ECR) is lower than the actual compression ratio (ACR) for the files to be copied. In this case, MS-DOS underestimates the space available. To correct this problem, set the ECR equal to the ACR for the drive as follows:

      Start DoubleSpace by typing dblspace at the MS-DOS command prompt.
      Select the compressed drive you want to change and then choose the Change Ratio command from the Drive menu.

      The Change Compression Ratio dialog box appears.
      The default ratio is the ACR. Choose OK.

      You can also change the ECR from the MS-DOS command prompt. For more information, type help dblspace /ratio at the MS-DOS command prompt.

      NOTE: The above procedure causes MS-DOS to estimate free disk space more accurately and may also increase the number of FAT entries available. If the files to be copied are highly compressible, then you may need to make the ECR higher than the current ACR.

    The ECR is higher than the ACR for the files to be copied. In this case, MS-DOS overestimates the space available, and you must either delete files or enlarge the drive to free space. To enlarge the compressed drive, use the following steps:

      Start DoubleSpace by typing dblspace at the MS-DOS command prompt.
      Select the compressed drive you want to enlarge, then choose the Change Size command from the Drive menu.

      The Change Size dialog box appears. The New Free Space line shows how much free space the compressed and uncompressed drives will have if you choose OK.
      Specify a smaller number for New Free Space on the uncompressed drive. As you change this number, DoubleSpace adjusts the New Free Space amount for the compressed drive. When the New Free Space amount for both drives is what you want, choose OK.

      DoubleSpace enlarges the compressed drive.

      NOTE: The above procedure decreases the free space on the uncompressed (host) drive.

    The DoubleSpace drive is too fragmented. To correct this problem, use the commands DBLSPACE /DEFRAG /F and DBLSPACE /DEFRAG on the compressed drive as follows:

    NOTE: You may want to perform this procedure overnight. Defragmenting a large or badly fragmented drive can take a long time. (To defragment overnight, put both commands into a batch file.)

      Make the compressed drive your current drive.
      Type dblspace /defrag /f at the MS-DOS command prompt.

      DoubleSpace defragments the drive.
      When DoubleSpace finishes, type dblspace /defrag at the MS-DOS command prompt.
    DoubleSpace consolidates free space on the drive to leave as much free space as possible.
    No more FAT entries are available. To correct this problem, split the host drive into more compressed drives as follows:

    If the data on a compressed drive is reaching the 512-megabyte limit, reduce the size of the drive and then use the Create New command on the Compress menu to create a new drive from free space on the drive.
    Finally, certain programs or files may cause the "Insufficient Disk Space" message or may fail when they are installed on a DoubleSpace- compressed drive because their ACR is close to 1:1. These include the following:
      Many games by Sierra On-Line (also marketed as Dynamix or Coktel)
      Microsoft Mail Format (.MMF) files
      Encrypted data files
      Precompressed files (such as .ARC, .ZIP, .PCX, and .GIF files)
    Move highly compressible files to the compressed drives and leave files that compress poorly on uncompressed drives.
For more information on the ECR, ACR, and the space available on a DoubleSpace-compressed drive, see page 125 in the "User's Guide."

The products included here are manufactured by vendors independent of Microsoft; we make no warranty, implied or otherwise, regarding these products' performance or reliability.


"Microsoft MS-DOS User's Guide" for version 6 and 6.2, pages 125-126

README.TXT, Section 7.3

Modification Type: Major Last Reviewed: 6/2/2001
Keywords: msdos KB100911