Installing MS-DOS 6.2 over Stacker Version 3.11 (107526)
The information in this article applies to:
• Microsoft MS-DOS operating system 6.2
This article was previously published under Q107526
You are attempting to install MS-DOS 6.2 Upgrade or Step-Up on a system
that is running Stac Electronics Stacker version 3.11 and you receive an
error message as outlined below.
You are installing the Upgrade or Step-Up (BBS or retail version), your C
drive is compressed using Stacker 3.11, you have less than 4,200,000 bytes
free on the host drive for C, and at least 4,200,000 bytes free on drive C.
When you run Setup, you receive this error message:
You are installing the retail version of MS-DOS 6.2 Step-Up, your C drive
is compressed using Stacker 3.11, and you have at least 4,200,000 bytes
free on the host drive for C.
When you run Setup, it indicates that your MS-DOS files are located on the
host drive for C. For example on the "system settings" screen it shows:
MS-DOS Path: D:\DOS
If you proceed with the installation, Step-Up is unable to update
the MS-DOS files on the host drive and displays the following
error message for each file it cannot update:
You are installing the BBS Step-Up, your C drive is compressed using
Stacker 3.11, and you have at least 4,200,000 bytes free on the host drive
When your run Setup, you receive the following message:
At the time MS-DOS 6.2 was released, the current version of Stacker
was 3.1. Microsoft ensured MS-DOS 6.2 Upgrade and MS-DOS 6.2 Step-Up
can detect and install correctly over Stacker version 3.1 and earlier.
Since Microsoft cannot guarantee how MS-DOS will interact with future
versions of Stacker, MS-DOS 6.2 Setup is not designed to detect and
install over versions of Stacker later than 3.1.
Stac Electronics has released Stacker version 3.11, (the box and disks
still indicate version 3.1). You can tell the difference between Stacker
3.1 and 3.11 by the file dates and sizes. The file date for Stacker version
3.11 is 9/08/93 and the files are marked with the time 3:11 A.M. The
problems described above occur only with Stacker 3.11.
To work around this problem, contact STAC Electronics to obtain the
62STAC.EXE file, or follow the procedure below. You can order the
62STAC.EXE file from STAC Electronics, or you can download it from the
STAC Electronics bulletin board service at (619) 431-7405.
If you are going to obtain the 62STAC.EXE file, use your Uninstall disk to
uninstall MS-DOS 6.2, run 62STAC.EXE, and then reinstall MS-DOS 6.2.
62STAC.EXE temporarily updates the Stacker driver in memory, not on disk,
so you will need to run MS-DOS 6.2 setup immediately after running the
You can also work around this problem by using the Debug program to make
the Stacker driver report version 3.1 instead of 3.11. The following
procedure uses Debug to change the memory location that Setup is looking at
to determine the Stacker version.
• If you have not already done so, exit SETUP by pressing F3. If
necessary, boot from the Uninstall Disk 1 and follow the instructions
on the screen to return to your previous version of MS-DOS.
• At the command prompt, type the following command and press ENTER:
• Check the name column for the STACKER or STACHIGH program.
• Using the program name found in the previous step, type the following
command and press ENTER:
Make note of the "Segment" address displayed by this command, for
example, 0025F. You will need this address in a later step.
• At the command prompt, enter the following command and press ENTER:
This should bring you to the Debug hyphen "-" prompt.
• At the Debug prompt, type the following command and press ENTER
where <ssss> is the last four digits of the segment address displayed
in step 4. For example, if the segment address from step 4 was 0025F,
Debug displays a segment:offset pair, for example, 025F:0A4A.
• Type the following command at the Debug prompt and then press ENTER
where <ssss:oooo> is the segment:offset displayed by step 6.
Debug will display a block of information similar to:
025F:0A40 5A A5 37 01 D0 00
025F:0A50 08 01 14 01 03 02 76 10-00 00 03 00 A4 09 20 6D
025F:0A60 00 00 00 00 00 00 00 00-00 0A 00 00 00 0A 00 00
025F:0A70 20 63 00 00 00 02 00 40-E0 69 3A 00 CD 13 CD 14
025F:0A80 CD 01 CD 03 1A 00 02 03-00 00 81 07 03 01 14 00
025F:0A90 CA 00 00 80 5E 19 00 00-00 00 00 00 53 57 41 50
025F:0AA0 00 01 02 03 04 05 06 07-08 03 0A 0B 0C 0D 0E 0F
025F:0AB0 10 11 12 13 14 15 16 17-18 19 00 00 B0 03 F9 01
025F:0AC0 00 00 00 00 00 00 24 01-01 01
Looking across the top row of this block, you should see the "5A A5 37
01" pattern. If you see this pattern, proceed to step 8.
If you do not see this exact pattern and more than one segment:offset
pair was displayed by step 6, repeat step 7 for each segment:offset
pair until you locate the memory block that contains this pattern.
If you do not see this exact pattern, and you have checked all
segment:offset pairs displayed by step 6, exit Debug by pressing Q and
ENTER. Contact Stac Electronics to obtain the 62STAC.EXE file.
• After locating the pattern as described in step 7, type the following
command at the Debug prompt and press ENTER
where <ssss:oooo> is the segment:offset pair used in step 7.
Debug displays the following (the segment:offset varies):
• Press the SPACEBAR two times. Debug displays the following:
025F:0A4A 5A. A5. 37.
IMPORTANT: If you do not see the "5A. A5. 37." pattern, press ENTER to
return to the Debug hyphen prompt. Then press Q and ENTER to quit
Debug. Contact Microsoft MS-DOS technical support for further
• Type 36 and press ENTER. This returns
you to the Debug hyphen prompt.
• Press Q and ENTER to quit Debug.
DO NOT restart your computer. If you do, you must go through this
• Run the MS-DOS 6.2 Setup program.
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