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Q106126: DoubleSpace DoubleGuard Error Codes

Article: Q106126
Product(s): Microsoft Disk Operating System
Version(s): MS-DOS:6.2,6.22; WINDOWS:95
Operating System(s): 
Keyword(s): msdos win95
Last Modified: 17-DEC-2000

-------------------------------------------------------------------------------
The information in this article applies to:

- Microsoft MS-DOS operating system versions 6.2, 6.22 
- Microsoft Windows 95 
- Microsoft Plus! for Windows 95 
-------------------------------------------------------------------------------

This information applies to both Microsoft DoubleSpace and Microsoft
DriveSpace. For MS-DOS 6.22, use DRVSPACE in place of DBLSPACE for
commands and file names.

SUMMARY
=======

If a DoubleGuard Alarm message appears, DoubleGuard has detected that an
application has damaged memory that DoubleSpace was using. DoubleGuard halts
your computer to prevent any further damage to your data.

This article contains information about the four possible DoubleGuard Alarm
messages.

MORE INFORMATION
================

The DoubleGuard Alarm message reads as follows

  DoubleGuard Alarm #<nn>

  A program has corrupted memory belonging to DoubleSpace. Further disk activity
  could result in the loss of some or all of the data on your drive. Therefore,
  DoubleGuard has halted your computer. For more information, see the
  README.TXT file

where <nn> is 13, 14, 15, or 16.

These errors occur when DoubleSpace detects that a software application, device
driver, or terminate-and-stay-resident (TSR) program has corrupted memory used
by DBLSPACE.BIN.

  DoubleGuard Alarm Number  Area Corrupted
  ----------------------------------------
  13                        BitFAT buffer

  14                        MDFAT buffer

  15                        File Fragment List

  16                        DBLSPACE.BIN Code Block


The following programs are known to cause a DoubleGuard Alarm errors:

Program                         More Information
----------------------          ----------------------------------------
Qemm (in Stealth mode)          Contact Quarterdeck Office Systems for
                               an upgrade
Vertisoft SpaceManager 1.53     Causes DoubleGuard error #15 when used
                               on a 286 machine running MS-DOS 6.2


Text from the MS-DOS 6.2 README.TXT:

7.19  You receive a DoubleGuard Alarm message
---------------------------------------------

If a DoubleGuard Alarm message appears, DoubleGuard has detected that an
application has damaged memory that DoubleSpace was using. DoubleGuard halts
your computer to prevent any further damage to your data.

Normally, each program "owns" a separate area of memory, and does not use memory
that another program is already using. However, a few programs contain
programming errors that cause them to inadvertently use memory belonging to
another program. If such a program inadvertently uses memory belonging to
DoubleSpace, that program could write its own data over the data DoubleSpace was
storing there. Since the data that DoubleSpace stores in memory usually includes
files you are currently using, this could cause damage to your data.

DoubleSpace's DoubleGuard safety-checking feature detects when another program
has violated DoubleSpace's memory, and immediately shuts down your computer to
minimize the chance of data loss. (If further disk activity were to occur
instead, you could lose some or all of the data on your drive, since the data
DoubleSpace has in memory is probably invalid due to damage by the other
program.)

If you receive a DoubleGuard Alarm message, do the following:

1. Restart your computer by turning the power switch off and then on again.

2. Type the following at the command prompt:

  " SCANDISK /ALL " (without the quotation marks)

  NOTE: If you are using Windows 95, restart your computer to a command prompt
  before typing this line.

  This runs ScanDisk on all your drives to detect and correct any problems that
  might have been caused by the program that violated DoubleSpace's memory.

3. Make a note of which program, if any, you were running when the DoubleGuard
  Alarm occurred. That program is probably (but not necessarily) the program
  that caused the DoubleGuard Alarm. If you receive additional DoubleGuard
  Alarms, take notes about what you were doing and see if you can detect a
  pattern.

Additional query words: tshoot 6.20 dblguard double guard spaceman

======================================================================
Keywords          : msdos win95 
Technology        : kbWin95search kbGamesSearch kbPlusSearch kbZNotKeyword3 kbPlus95 kbMSDOSSearch kbMSDOS622 kbMSDOS620
Version           : MS-DOS:6.2,6.22; WINDOWS:95

=============================================================================

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