ID:AB Intel AboveBoard Plus
Quarterdeck Technical Note #150 Filename: AB_PLUS.TEC
by Stan Young CompuServe: ABPLUS.TEC
Last revised: 2/10/92 Category: HW3
Subject: A full description of how to set up the AboveBoard Plus for use with
DESQview and QRAM.
Q: How do I set up my Intel AboveBoard Plus to best support DESQview or for
use with QRAM?
The Intel AboveBoard Plus supports in hardware many of the features of
the EMS 4.0 software specification that DESQview and QRAM would like to use.
It is capable of mapping EMS memory below the 640K barrier to support
DESQview's multitasking. It also can map EMS memory into high memory
addresses above 640K and below 1 Megabyte, a feature which is useful to both
DESQview and QRAM in order to get more DOS memory. Obtaining these features,
however, requires that the board be set up in specific ways, and there are
some restrictions in the way the board and driver work that are important to
1. Backfilling Motherboard Memory:
Backfilling motherboard memory is NOT important to the operation of QRAM.
But, as in the examples given in Appendix B of the DESQview manual, for
Enhanced Expanded Memory Boards if you want to have large expanded memory
partitions in which you can multitask programs, it is necessary to disable
motherboard memory and have the AboveBoard Plus fill memory out to 640K. The
lowest the AboveBoard Plus will place EMS4 pages is from 256K, so it is not to
your advantage to backfill any lower than that, even if your machine will
support backfilling from a lower address. If your machine will allow the
board to fill out from 256K, you will be able to get expanded memory
partitions of 384K. Unlike the examples in the manual shown for EEMS cards,
the partitions will be 384K regardless of the type of video card you have, as
the Intel hardware will not allow for any EMS expanded memory pages to be
mapped into the video areas. Once the board is backfilling motherboard memory
addresses, one very important configuration item remains relative to the
driver. You must specify the "MC" (Map Conventional) parameter to the EMM.SYS
driver. Reference to this parameter is somewhat buried in the Intel manual,
but this parameter must be specified in order to have the driver set expanded
memory pages in the 256K-640K range.
2. Set the "Page Frame" as low as possible:
This is important for BOTH DESQview and QRAM users. The AboveBoard Plus
driver will only map memory above 640K as one contiguous block, starting with
the original 64K EMS page frame. For any other memory to be mapped, it must
be directly above and contiguous with the page frame. This may be changed in
a future release of the driver, as other EMS 4.0 drivers are not so
restrictive as to where the additional memory resides.
Because of this requirement, and because some versions of the Intel
installation program default the page frame to a "D000" address, memory
addresses that might be mapped may be bypassed. To get best use from the
memory, set the page frame as low as possible.
The AboveBoard driver which became available when Intel started shipping
QRAM with its boards defaults the frame to the lowest possible address.
Upgrade drivers are available from Intel directly and are posted on Intel's
electronic bulletin board.
If you do not have such a driver, we have determined that the easiest way
to be sure the frame is low is to change the CONFIG.SYS file so the the frame
assignment (usually D000) is set to C000. While it is often the case that a
C000 page frame setting might be in conflict with video ROMS or other
installed devices, it is our observation that the Intel driver generally
detects these devices and on boot will determine that the setting is
inappropriate and will select instead the lowest frame setting that is free --
just what we wanted. This method, while easy, may not be fool-proof, so if
you encounter difficulty with the frame the Intel driver selects, you will
have to do some digging into your hardware documentation to see what area
might be available.
3. Install the QEXT.SYS driver:
Assuming you have an AT, you can configure some of the Intel AboveBoard
Plus memory as exTENDed memory. By loading the QEXT.SYS driver in your
CONFIG.SYS file (see page 148 in the DESQview manual), this driver allows you
to take 60K of extended memory and make it available for running some of
DESQview's code, thus lowering the overhead of DESQview in DOS and increasing
your Maximum Available Conventional Memory by 60K as shown by the Memory
Early versions of the AboveBoard Plus only allow you to configure
extended memory in increments of 512K, so on these systems, you have to
reserve 512K of extended memory to support the 64K QEXT driver. The remaining
memory might be used as a VDISK, or by a disk cache, but will not be available
as expanded memory. Intel now ships boards which can allocate memory in 128K
segments, and an upgrade for existing boards is available.
If you have other extended memory on the machine, you may not want to
allocate any of the AboveBoard as extended memory. You would simply install
the QEXT.SYS driver and as long as the extended memory starts at 1 megabyte
(1024K), QEXT will use it.
As is usual, when using an expanded memory system, you will want to load
DESQview using the XDV.COM loader as indicated on page 139 of the DESQview
manual. The settings above should allow you to get the best memory sizes for
DESQview. Your Memory Status program will probably show figures somewhat less
than listed in the DESQview manual. This is because the AboveBoard Plus will
not map into the video memory area, but the memory obtained in the windows
should be adequate for most purposes.
Intel Tech Support: 800-538-3373
Intel BBS: 503-645-6275
Intel Support FAX back: 503-629-7576
*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 by Quarterdeck Office Systems *
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