DoubleSpace Cannot Mount Compressed Write-Protected Disk

• Microsoft MS-DOS operating system versions 6.0, 6.2
• Microsoft Windows 95

SYMPTOMS

When you try to mount a write-protected disk with DoubleSpace, you receive the following error message:

   DoubleSpace cannot mount drive <x> because the file
   <x>:\DBLSPACE.nnn is not a valid compressed volume file.

When you try to mount a write-protected removable media disk under MS-DOS 6.2, you receive the following error:

   Dblspace cannot mount drive <drive letter>:
   The <drive letter>:\Dblspace.000 file is not a valid compressed
   volume file.  To fix it, type scandisk X:\Dblspace.000 at the
   command prompt.

WORKAROUND

To work around this problem, remove the write protection for the disk.

MORE INFORMATION

When DoubleSpace mounts a compressed volume file (CVF), it ensures the Microsoft DoubleSpace BIOS parameter block (MDBPB) (the overall configuration sector) and the BitFAT (a table of available heap sectors) are current. To do this, DoubleSpace must write to the disk. This feature is under review and will be considered for inclusion in a future release.

You can mount a floppy disk by running DoubleSpace, or you can mount the floppy disk with the MS-DOS DBLSPACE /MOUNT command. For example, type the following command at the MS-DOS command prompt and press ENTER if your floppy disk drive is drive A:

   dblspace /mount a:

STATUS

This behavior is by design.