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- ID:P2 Considerations on PS/2 Machines
- DESQview/QEMM Technical Note
-
-
- Note: These comments are specific to IBM Models 50, 50Z, 55SX,
- 60, 70 and 80 and compatibles that have the "Microchannel"
- motherboard. They do not apply to AT's, PC's, XT's, or
- compatibles or PS/2 Models 25, 30 or 30-286 which use standard
- architecture.
-
- For the most part, if you are running DESQview or QEMM
- (Quarterdeck Expanded Memory Manager 386) on PS/2 machines, you
- follow the same rules set forth in the DESQview manual for
- running on machines with the standard architecture, however there
- are a few areas where setup for these machines differ.
-
- 1. Optimize Communications: Microchannel machines have a
- different interrupt structure than standard architecture
- machines. If you are running a version of DESQview prior to
- 2.23, when configuring the DESQview Setup program (under
- Performance), you should always be sure the option "Optimize
- Communications" is set to "N". Setting this option to "Y"
- will result in errors reading your floppy drives. Versions of
- DESQview after 2.23 handle this difference in interrupt structure
- and allow you to set the option to "Y" for microchannel machines.
-
- 2. IBM Cache: The IBM Cache uses exTENDed memory (not exPANDed)
- and if loaded after our Expanded memory manager (QEMM), will not
- see any memory if you have not taken steps to reserve some
- extended memory for the use of the cache.
-
- If you load the cache first, it will see and use extended memory,
- but if QEMM is loaded after it, the cache is confused by the
- memory mapping done by QEMM and this will result in disk errors.
- Therefore, you should be sure you are loading IBMCACHE after
- QEMM.SYS.
-
- If you are using the IBM Cache on a 386 PS/2 with QEMM, load QEMM
- first and use the "EXTMEM" or "MEMORY" option to reserve the
- amount of memory you want to allocate to the cache. Then load
- the cache, allocating to it the amount of memory you have
- reserved. Loaded in this fashion, the cache should operate
- properly.
-
- This configuration should also be followed if loading other
- caches that use extended memory on the PS/2. Naturally, if you
- use a cache that uses exPANDed memory, you would have to load the
- cache after QEMM and you would not need to reserve any exTENDed
- memory.
- Copyright (C) 1990 by Quarterdeck Office Systems
- * * * E N D O F F I L E * * *