Category : Alternate Operating Systems - Quarterdeck DesqView, CP/M, etc
Archive   : QTEC9306.ZIP
Filename : QEMM5060.TEC

ID:QE QEMM-50/60 Hardware Requirements
Quarterdeck Technical Note #186 Filename: QEMM5060.TEC
by Todd Threadgill CompuServe: Q5060.TEC
Last revised: 1/24/92 Category: QEMM

Subject: An examination of the features and hardware requirements of
QEMM 50/60, Quarterdeck's expanded memory manager for IBM PS/2
Models 50 and 60.


Quarterdeck Expanded Memory Manager 50/60 (QEMM-50/60) is a sophisticated
program that provides expanded memory for IBM PS/2 Models 50 and 60 without
requiring the purchase of a special expanded memory board. In order to work
its magic, however, QEMM-50/60 does have certain hardware requirements that
may be confusing to users. This document is intended to provide a clear and
concise guide to these hardware requirements.


Q: Does QEMM-50/60 work on all PS/2 computers?

A: As its name suggests, QEMM-50/60 only works on IBM PS/2 Models 50, 50Z, and
60. If you have a Model 55SX, you should use Quarterdeck Expanded Memory
Manager - 386 (QEMM-386) for your memory management needs, since the Model
55SX has an 80386SX processor. If you have a Model 30 or 30-286, the
combination of an EMS 4.0 exPANDed memory board and Quarterdeck's QRAM product
will provide most of the features of QEMM-50/60. The memory boards required
by QEMM-50/60 are NOT compatible with either Model 30 PS/2 computer.


Q: I have 2 megabytes of memory on my computer's motherboard. Why doesn't
QEMM-50/60 work?

A: The memory on the Model 50/60 motherboard above 640K is exTENDed memory.
On 80286 computers like the 50 and 60, this memory is essentially useless to
DOS programs. Some programs can access exTENDed memory through the use of DOS
extenders, but these are the exception rather than the rule.

However, QEMM-50/60 can make the exTENDed memory on certain expansion cards
behave like exPANDed memory. These cards have special hardware on them that
give them the capability to "rearrange" memory, should one of the chips on the
motherboard or memory card go bad. The hardware that does this "rearranging"
is very similar to expanded memory hardware, but was not designed with that
idea in mind. QEMM takes advantage of this special hardware feature to make
the exTENDed memory look like exPANDed memory.

QEMM-50/60 Version 5.0 works with the following memory cards:


Adapter Memory Board
ID Capacity Name
--------------------------------------------------------------------------
FEFE 0.5-2MB IBM PS/2 80286 Memory Expansion Option
F7FE 2-8MB IBM PS/2 80286 Expanded Memory Adapter /A
F7FE 0-8MB IBM PS/2 0-8MB Expanded Memory Adapter /A
F7F7 2-8MB IBM PS/2 2-8MB 80286 Memory Expansion Option
7011 0-2MB Tecmar MicroRAM
7048 0-8MB Edsun Labs EL2010 chip set
7049 0-8MB Edsun Labs EL2010 chip set
76DA 0-4MB Quadram QuadMEG PS/Q
76DE 0-4MB Quadram QuadMEG PS/Q
7F7E 0-8MB Orchid RamQuest Extra

Version 6.0 of QEMM-50/60 adds support for the following cards:

Adapter Memory Board
ID Capacity Name
---------------------------------------------------------------------------
F7F7 1-8MB IBM PS/2 1-8MB 80286 Memory Expansion Option
7011 0-8MB Tecmar MicroRAM A/D
7050 0-8MB AST RampagePlus/MC
7051 0-8MB AST RampagePlus/MC with I/O Pak/MC-S Option
7052 0-8MB AST RampagePlus/MC with I/O Pak/MC-SP Option
70D1 0-32MB Intel AboveBoard MC
70D4 0-16MB Kingston Technology KTM-609
(KTM-609 Rev C or equivalent Engineering
Change is required)
7788 0-8MB Intel AboveBoard 2 Plus
7B7F 0-8MB Memory Adapter for Micro Channel Architecture
7CEF 0-128MB Capital Equipment OS/RAM32plus
7D7F 0-8MB Orchid RamQuest Extra 16/32

Note that the Edsun Labs entries are not actually boards, but rather chip
sets that are used by some board manufacturers.


It is important to note that several of the boards listed above (the AST
RampagePlus boards and the Kingston Technology KTM-609) feature "granularity"
of 512K and 1024K, respectively. The term "granularity" refers to the
smallest amount of memory that a particular board can map. The other boards
have a granularity of 16K, which means that users can allocate memory in 16K
chunks. The disadvantage of larger granularity (such as 512K or 1024K) is a
lack of freedom when allocating memory for specific tasks. For example, when
allocating XMS memory for a RAM disk, it is often advantageous to allocate
only that which is needed as XMS memory, and leave the rest as EMS memory.
With a 16K-granular board, this is quite easy, as users can allocate memory in
16K chunks (i.e. 16K, 32K, 256K, etc.). Users of the AST and Kingston boards
must allocate at least 512K (or 1024K), even if only 256K is needed. Thus it
is easy to see that a board's granularity is an important consideration. QEMM-
50/60 cannot affect a board's granularity, and the rules remain the same
whether QEMM-50/60 is present or not.

Note: The AST and Intel boards are standard expanded memory (EMS) boards and,
unlike the other boards listed above, do not comply with the XMA
specification. The author of QEMM-50/60 Version 6.0 has reverse-engineered
these boards' respective expanded memory managers so that QEMM-50/60 is able
to manage them. In the case of the Intel AboveBoard and AST RAMpage, QEMM-
50/60 is "filling in" as a replacement expanded memory manager, with more
features than Intel's or AST's own EMM software.

As an alternative to one of the boards listed above, a hardware upgrade will
allow you to access all of your motherboard memory as well as the memory on
any expansion cards you may have installed. Products such as the All
Chargecard and the SOTA Pop card will provide such memory access, as will a
conversion to a 386SX processor.


Q: I have different memory boards from different manufacturers on the same
machine. I'd like to use all of the memory with QEMM-50/60. Will I be able
to?

A: Yes. QEMM-50/60 allows you to mix boards from different manufacturers
together and use them ALL as expanded memory. This cannot be done with any
other EMM driver.


Q: I'm thinking of getting an exPANDed memory card for my PS/2. Will QEMM-
50/60 work with it?

A: Yes, if the board appears on the list of supported boards above.
Otherwise, no -- exPANDed memory cards come with their own EMM drivers.


Q: Do I need to disable my motherboard memory in order to use QEMM-50/60?

A: Not for regular use of exPANDed memory. However, in order to multitask
successfully on 80286 systems with Quarterdeck's DESQview environment,
reducing the amount of conventional memory is recommended. (While it is
possible to multitask under DESQview using only conventional memory, one is
limited to running programs that can fit together into 640K minus DESQview's
own overhead.) When conventional memory is reduced, expanded memory can fill
in the rest up to 640K, and multiple programs can be run in exPANDed memory.
If you are planning on multitasking with DESQview, remove the "X=0000-9FFF"
parameter from the QEMM.SYS line in your CONFIG.SYS file, and QEMM-50/60 will
automatically take care of everything for you.


************************************************************************
*This technical note may be copied and distributed freely as long as it*
*is distributed in its entirety and it is not distributed for profit. *
* Copyright (C) 1991-2 by Quarterdeck Office Systems *
************************ E N D O F F I L E *************************