ID:XT XtraDrive and QEMM-386
Quarterdeck Technical Note #199 Filename: XTRADRV.TEC
by Robert Gaustad CompuServe: XTRADR.ZIP
Last revised: 26 April 1993 Category: QEMM
Subject: Frequently asked questions about QEMM-386 and XtraDrive.
XtraDrive is a disk compression program published by Integrated Information
Technology. While this program is generally compatible with QEMM-386,
QEMM-50/60 and QRAM, some issues must be addressed. Below are some of the
most frequently asked questions about XtraDrive and QEMM-386. Throughout this
document we will refer to QEMM-386. With the exception of QEMM-386's Stealth
feature, the same solutions presented for QEMM-386 will also apply to users of
QEMM-50/60 or QRAM. The Optimize program is the same for all three products.
Note that the Stealth option exists only with QEMM-386.
FREQUENTLY ASKED QUESTIONS ABOUT QEMM-386 AND XTRADRIVE
Q: When I try to install XtraDrive on a system that has QEMM-386 and
Stealth running, I get the following error message:
"Drive 1 is being controlled by a program that appropriates INT13. You
cannot install XtraDrive on this drive."
What do I have to do to fix this?
A: Remove the ST:M or ST:F parameter from the QEMM-386 device line and
try to install again. This only needs to be removed during the installation
Q: So, I can use XtraDrive with QEMM-386's Stealth parameter?
A: Under most circumstances, Stealth works fine with XtraDrive, but if you
are using the XtraDrive EMS cache you cannot use QEMM-386's Stealth parameter.
The XtraDrive EMS cache accesses the disk via the page frame and this causes a
conflict with Stealth. Normally, if a program accesses the disk via the page
frame, QEMM-386's DBF=2 parameter will fix the problem. This is not possible
with XtraDrive. The EMS cache will also cause problems with drivers such as
EMSNETX.COM and Microsoft's MOUSE.COM using EMS.
Q. Are there any other possible conflicts with XtraDrive and QEMM-386's
A. Under certain rare circumstances you may need to exclude a 4K region in
the system ROM BIOS area. If after installing XtraDrive and QEMM-386 with the
Stealth parameter, you get an Exception 13 or lockup, then get the Quarterdeck
Technical Bulletin #205, STEALTH.TEC. This will help you find out which area
to exclude. Keep in mind, however, that the need to exclude the 4k block of
High RAM is very rare.
Q: When I install QEMM-386 on a system that has XtraDrive currently
installed, I get a lockup or Exception 13 when I reboot the machine, loading
QEMM-386. What do I have to do to allow me to boot the system?
A: Simply reboot the machine and when it beeps after checking the memory,
hold down the ALT key until prompted to press ESC to unload QEMM-386. Once
you have unloaded QEMM-386, load your CONFIG.SYS file into a text editor. If
you have MS-DOS 5 or MS-DOS 6, you may load the DOS Editor, by typing
EDIT C:\CONFIG.SYS and
the following parameter: X=9000-9FFF.
A sample QEMM-386 device line would then read as follows:
DEVICE=C:\QEMM\QEMM386.SYS RAM ST:M X=9000-9FFF
After adding the parameter, simply save the CONFIG.SYS file and reboot your
Q: When I installed XtraDrive after QEMM-386, XtraDrive placed an exclusion
from 8000-A000 on the QEMM-386 device line. Do I need this exclusion and will
it take away any memory from my system?
A: Given the way that XtraDrive is currently designed, an exclusion is
needed. If you are using DESQview or DESQview/X, the exclusion will tell
QEMM-386 to not map memory into that area, so the amount of memory available
to each DESQview window will be smaller. There are a couple of things you can
do to increase your window size if you are using DESQview or DESQview/X:
1. The default exclude is 8000-A000, a 128K block. Testing has
determined that usually an exclusion of 9000-9FFF will be sufficient. This
will decrease your window size by only 64K. If you are using the CONVENTIONAL
MEMORY disk cache, and have selected more than (2) 16K blocks of conventional
memory, you will need to change the exclude back to 8000-9FFF.
2. Load the XtraDrive driver BEFORE QEMM-386 and take the exclude off the
QEMM-386 device line. This should decrease your window size by only about
46K. Once again, if you are using the CONVENTIONAL MEMORY disk cache, your
driver size will increase with each 16K block you add. The default is (1)
16K block. If you select (2) blocks, your driver will be 66K. If you
select (3) it will be 82K. The maximum, (4) 16K blocks will result in a 98K
driver. Your DESQview and DESQview/X window sizes will decrease accordingly.
Q: If I have a SCSI bus-mastering controller, can I load the XtraDrive device
driver into High Ram?
A: No. Even with double buffering, with a SCSI bus-mastering device, you
will not be able to load XtraDrive into High Ram. This is NOT a memory
manager issue, but a problem with XtraDrive.
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*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) 1993 by Quarterdeck Office Systems *
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