Mr. Know-It-All - March 2005
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Copyright 2019, Southern California OS/2 User Group. ALL RIGHTS RESERVED.

SCOUG, Warp Expo West, and Warpfest are trademarks of the Southern California OS/2 User Group. OS/2, Workplace Shell, and IBM are registered trademarks of International Business Machines Corporation. All other trademarks remain the property of their respective owners.

The Southern California OS/2 User Group
P.O. Box 26904
Santa Ana, CA 92799-6904, USA

March 2005


 Dear Mr. Know-It-All 

Mr. Know-It-All has the answers to even the really tough questions.


Question:

As you probably know, the last native version of Partition Magic was version 3.05 and it does not run on many current systems. However, the interface is nice and it would be handy to have it available for the things it does well. Can anything be done to make it run again?

Answer:

Of course there is. Knowing how OS/2 users like their older software, Mr. KIA devoted some time to tracking down a workaround. It turned out to be a relatively simple bit of defect analysis.

The consensus on the mailing lists and newsgroups has always been that the native Partition Magic will not run if the system has more than 256MB of RAM installed. This turns out to be mostly true although the limit will vary. If one uses the PQPIPE utility supplied by PowerQuest to monitor the diagnostic log messages one will see that the last thing Partition Magic does before failing is attempt to allocate a large quantity of private memory space. This allocation fails and the failure is not handled correctly and Partition Magic traps. It appears that this code path was not well tested.

The allocation quantity will be the smaller of the physical RAM size and the resident memory size. In today's systems, the allocation quantity will always be the physical RAM size.

Hindsight tells us that this implementation was not the best possible design choice. It does not take into account OS/2's per application 512MB linear address space limit. This limit usually results in OS/2 applications having something under 300MB of available private address space.

The workaround is to patch PQMAGICO.EXE and PMAGICOT.EXE to do a fixed allocation of 192MB.

Here are the patches:

FILE PQMAGICO.EXE
VER 365D3 8B44240439E87606
CHA 365D3 B80000C000909090
VER 365DB 8D850000FFFF
CHA 365DB 909090909090
FILE PMAGICOT.EXE
VER 15EC6 39E876068D850000
CHA 15EC6 B80000C000909090
VER 15ECE FFFF
CHA 15ECE 9090

These patches work for the following version 3.05.302 executables:

 3-05-98  13:33         512,478           0  PMAGICOT.EXE
 3-05-98  13:53         894,541           0  PQMAGICO.EXE

To use these patches, copy each to a text file with a convenient name. Make a copy of your original executables and apply the patch with IBM's PATCH utility. The command line syntax is:

  PATCH patchfile /A
where patchfile is the name you gave the patch file.

Interestingly, Partition Magic does not hang on to the allocated memory. Theseus/2 shows a much smaller memory utilization once the applications are running. The PQPIPE output also shows subsequent attempts to tune the memory usage.

While it appears that the patch is sufficient to stabilze the programs, there are no guarantees. Take the usual precautions before allowing the patched programs to modify drive content.

Also, as often noted, Partition Magic is not LVM aware. If you have an LVM aware system, be prepared to restore the LVM data after allowing Partition Magic to modify drive content.

That said, it actually turns out that Partition Magic is not entirely LVM unaware. The PQPIPE output shows references to LVM data. It would appear that, at one time, PowerQuest planned to fully support LVM.


Curious or in doubt, you can ask Mr. Know-It-All
OS/2 is his specialty and sharing solutions is his passion
Mr. Know-It-All lives in Southern California.


The Southern California OS/2 User Group
P.O. Box 26904
Santa Ana, CA 92799-6904, USA

Copyright 2005 the Southern California OS/2 User Group. ALL RIGHTS RESERVED.

SCOUG, Warp Expo West, and Warpfest are trademarks of the Southern California OS/2 User Group. OS/2, Workplace Shell, and IBM are registered trademarks of International Business Machines Corporation. All other trademarks remain the property of their respective owners.