home
***
CD-ROM
|
disk
|
FTP
|
other
***
search
/
The Original Shareware 1.1
/
The Original Shareware (WeMake CDs)(Volume 1.1)(CDs, Inc)(1993).iso
/
36
/
qostnote.zip
/
XDV2.TEC
< prev
next >
Wrap
Text File
|
1990-07-03
|
3KB
|
85 lines
ID:X2 Discussion of DV.EXE vs. XDV.COM
--------------------------------------
XDV.COM, which is sometimes renamed to DV.COM as recommended in
Quarterdeck's documentation, is a loader that places bits of
DESQview code in high memory areas. It is useful on any system
that has expanded memory, or on any system that has extended
memory and is using DESQview's QEXT.SYS driver. If DESQview
loads successfully when started with the DV.EXE file but not when
started with XDV.COM or DV.COM, there are two likely
possibilities:
1) The system's expanded memory manager (EMM) has allowed
DESQview to place a piece of its code in an area between 640K and
1024K (known as the reserved memory area) that is already being
used by hardware in the system;
2) QEXT.SYS is conflicting with another program that is using the
first 64K of extended memory.
In the first case, one must determine which part of the area
between 640K and 1034K is in conflict, then exclude it using the
expanded memory manager's parameters. If you know the hardware
in the system, you should consult the manuals (or the
manufacturers) of the expansion boards in the machine to
determine the addresses that are being used for ROM extensions,
buffers, etc.
Failing this, you should use the /X parameter to XDV.COM to
exclude different areas of reserved memory, making the exclusions
smller and smaller until the conflict is pinpointed. Like most
memory managers, XDV.COM takes hexadecimal addresses; in
hexadecimal, the range A000-FFFF represents the addresses between
640K and 1024K. Thus the command line
XDV /X:A000-FFFF
prevents DESQview from putting its code anywhere between 640K and
1024K.
XDV /X:A000-CFFF
excludes the first half of this area, and
XDV /X:D000-FFFF
excludes the second half.
All the possible 16K areas that can be excluded on XDV.COM are
listed below.
A000-A3FF A400-A7FF A800-ABFF AC00-AFFF
B000-B3FF B400-B7FF B800-BBFF BC00-BFFF
C000-C3FF C400-C7FF C800-CBFF CC00-CFFF
D000-D3FF D400-D7FF D800-DBFF DC00-DFFF
E000-E3FF E400-E7FF E800-EBFF EC00-EFFF
F000-F3FF F400-F7FF F800-FBFF FC00-FFFF
To exclude a number of these consecutive ranges, use the
endpoints of the first and last block that you want to exclude.
For instance:
XDV /X:A000-ABFF
excludes the first three 16K areas above 640K.
To determine if QEXT.SYS is in conflict with anything in the
system, use this special exclusion on XDV:
XDV /X:FFFE
Since the Quarterdeck Expanded Memory Manager-386 (QEMM-386) and
other expanded memory managers for 80386 machines allow DESQview
to place code in the QEXT area without the actual presence of the
QEXT.SYS driver, this exclusion should be tried when
troubleshooting 80386 machines in general.
If the /X:FFFE exclusion eliminates the problem, look in the
CONFIG.SYS and AUTOEXEC.BAT files for drivers or terminate-and-
stay-resident programs that may be using extended memory. If a
program is in conflict with QEXT.SYS, the program may take
parameters that will prevent it from using the addresses between
1024K and 1088K, which QEXT.SYS must use.