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Quarterdeck Patch For QEMM-386 5.10, 5.11, An
DocumentID: 653590
Revision Date: 29-Feb-96 8:29:24 PM

The information in this document applies to:
WordPerfect® 5.1 for DOS

Problem

Solutions: When a customer uses the patch for QEMM-386 5.10, 5.11, and 5.12 to resolve problems with programs that make EMS 4.0 calls to move or exchange zero-length memory regions, Quarterdeck will cause WP 5.1 to reboot with the message appearing, "Are Other Copies Of WP Currently Running?"

The EMS (Expanded Memory Specification) 4.0 provides a call (function 24) which programs can make to move information from one region of memory to another, or to exchange information between two regions of memory.

Users of QEMM-386 versions 5.10 - 5.12 may experience system instability when a program makes the Function 24 EMS call to move or exchange a region of memory that is zero bytes in length. Generally the system will crash. There is not a good reason to use Function 24 on a region of length zero, but such a situation may occur when a program uses the same subroutine to implement Function 24 in a variety of different situations.


Note:      Users of versions of QEMM-386 after version 5.12 should not experience this problem. Do not use this patch for QEMM-386 5.0 or earlier, or on any version of QEMM-386 later than 5.12. Use the DIR command to check the date on the QEMM386.SYS file.

            If the date on the file is 5:10 am, 5:11 am or 5:12 am, use the patch. If there is no QEMM386.SYS file in the directory, or if the date on the file is later than 5:12 am, you probably have an earlier or later version of QEMM-386.


The following procedure is intended to prevent system crashes when EMS 4.0 Function 24 is used.

1.      Make a copy of the QEMM386.SYS file in your QEMM directory as a backup by renaming QEMM386.SYS to QEMM386.OLD.
2.      At the DOS directory prompt, type:
      DEBUG C:\QEMM\QEMM386.SYS and press Enter. The DEBUG prompt will appear as a hyphen (-).
3.      At the DEBUG prompt, type:
      S 100 L F000 8B CB 0B DA 74 F0, and press Enter. DEBUG will return a segment address and an offset: XXXX:YYYY. XXXX:YYYY is used as an example.
4.      At the DEBUG prompt, use the segment address and offset that was just returned to give the command:
      E XXXX:YYYY 8B CB OB DA 74 22. Press Enter.
5.      Type W and press Enter. DEBUG will announce that it is writing a certain number of types, then it will return the DEBUG prompt.
6.      Type Q and press Enter.


7.      To double-check your patch, type:
      COMP C:\QEMM\QEMM386.SYS C:\QEMM\QEMM386.OLD and press Enter.
      COMP will return:
      C:QEMM386.SYS and C:QEMM386.OLD
      Compare error at OFFSET XXXX
      File 1 = 22
      File 2 = F0
Eof mark not found
      Compare more files (Y/N)?

      The value XXXX after OFFSET will vary from version to version of QEMM 5.1, but the rest of the message should be the same. It states that there is exactly one byte difference between the file, and the different byte is 22 in QEMM386.SYS and F0 in QEMM386.OLD. If COMP returns the message "Files Compare OK," then you probably failed to use DEBUG's W command to save your change. If COMP returns more than one compare error, or if the bytes returned by the compare error don't match the above example, the procedure has failed.
8.      If the patch was successful, reboot your machine.
9.      Rename QEMM386.OLD to QEMM386.SYS.

Answer:

Details:


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