DoubleSpace Setup Hangs During First Reboot (98178)

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

This article was previously published under Q98178



You run DoubleSpace Setup and your computer stops responding (hangs) during the first reboot or your computer hangs when you boot from a floppy disk that contains the DBLSPACE.BIN file (such as the Uninstall disk or the MS-DOS 6 Upgrade Disk 1).

When this problem occurs, your system hangs before the DoubleSpace compression process begins. Because no data is ever moved to a DoubleSpace compressed volume file (CVF), no data is lost.


This situation may occur because the ROM BIOS on your computer failed when DBLSPACE.BIN called interrupt 1AH.

This problem occurs on the following computers:
    Canon models C-200 M-50 and C-200 M-55
    CompuAdd 386
    Computers using a Microsolutions Compaticard
    Positive computers
    Sharp models 6700, 6781, 6785, 6800, and 6881
    Some AEG Olympia 386SX Laptops
    Some older ACER machines
    Snap-on Intel 386 and Intel Above Board 2.0
    Texas Instruments (TI) TravelMate 2000
    Zeos 80386 with an AMI BIOS dated 09/15/89
NOTE: The above list may not be complete.


To work around this problem, do the following:

    Restart your computer from an MS-DOS system disk that does not contain the DBLSPACE.BIN file.
    Change to the root directory of your hard disk, then delete the DBLSPACE.* files from the root directory of your hard disk. For example, type the following at the MS-DOS command prompt and press ENTER:

    deltree /y c:\dblspace.*

    Edit your AUTOEXEC.BAT file and remove any DoubleSpace commands.
    Edit your CONFIG.SYS file and remove the following line:
          devicehigh=c:\dos\dblspace.sys /move

    Remove any floppy disks from your disk drives and restart your computer.
    Either use the following procedure to modify the MS-DOS 6 Upgrade DBLSPACE.BIN file so that it does not make the INT 1A ROM BIOS call, or upgrade to MS-DOS 6.2.

    If you are going to modify DBLSPACE.BIN, use Debug to load the DBLSPACE.BIN file into memory by typing the following at the MS-DOS command prompt, and then press ENTER:

    debug c:\dos\dblspace.bin

    Press ENTER after typing each of the following commands:
       Debug               Commands
       Prompts             to Enter    Comments
       -                    e c7ea      Edit C7EA
       nnnn:C7EA CD.        90          Replace INT opcode with NOP
       -                    e c7eb      Edit C7EB
       nnnn:C7EB 1A.        90          Replace 1A INT number w/ NOP
       -                    w           Write the file back to disk
       Writing 0C80E bytes
       -                    q           Quit Debug
    If you have an international version of MS-DOS 6.0 DoubleSpace, the commands noted above do not work. To modify any version of the DBLSPACE.BIN file, use Debug to load DBLSPACE.BIN into memory and press ENTER after typing each of the commands listed below:
       Debug Prompts           Commands to Enter
       -                       r cx
       CX aaaa
       :                       <Press the ENTER key>
       -                       s cs:100 L <aaaa value shown above> CD 1A
       -                       e (eeee value shown above)
       ffff:gggg nn.           90 <press SPACEBAR> 90
       -                       w
       Writing nnnnn bytes
       -                       q
    For example, if you use this script on the DBLSPACE.BIN file provided with MS-DOS 6 Upgrade, you would see the following:
          H:\>debug dblspace.bin
          -r cx
          CX C80E
          -s cs:100 L c80e cd 1a      18FD:0544
          -e c7ea
          18FD:C7EA CD.90   1A.90
          Writing 0C80E bytes

    Run DoubleSpace Setup again.


When DBLSPACE.BIN loads, it makes a call to Interrupt 1AH (Function B0H, Subfunction 01H) to check for the presence of a ROM-based MRCI provider. On systems that do not have a ROM-based MRCI provider, the ROM BIOS must process the INT 1AH call and indicate that the function was not successful. Microsoft has found that with some ROM BIOS chip sets, the stack becomes corrupted when this function call is processed.

The Debug procedure removes the INT 1AH call from DBLSPACE.BIN. On systems with no ROM-based MRCI provider, this does not alter the performance of DoubleSpace. The Debug procedure should not be performed on systems that have a ROM-based MRCI provider.

NOTE: At this time, no ROM-based MRCI providers are available on the market.

The following computers do NOT experience the problem noted above under MS-DOS 6.2:
    Microsolutions Compaticard
    Olympia Laptops
    Snap-on Intel 386 and Intel Above Board 2.0
    TI TravelMate
With MS-DOS 6.2, the check for a ROM-based MRCI server is disabled by default. If your computer has a ROM-based MRCI server, you can enable this check by typing the following at an MS-DOS command prompt:

dblspace /romserver=1

For more information on this command, type help dblspace /romserver at an MS-DOS 6.2 command prompt.

CAUTION: Do not enable the MRCI check with MS-DOS 6.2 unless you are certain that you have hardware that uses MRCI.

Modification Type: Major Last Reviewed: 11/19/1999
Keywords: KB98178