Tech Arsenal 1/Tech Arsenal (Arsenal Computer).ISO/tek-21/qwhite.zip/TOPS.TEC

Text File | 1992-03-09 | 9KB | 135 lines

ID:TP TOPS network, DESQview and QEMM 386
by TOPS Corp. Technical Support #163
April, 1989
last revision (at Quarterdeck):  12 February 1992

                                  OVERVIEW

DESQview is a multi-tasking windows environment for DOS-based machines, made
by Quarterdeck Office Systems in Santa Monica, CA.  It can be run on any
machine running DOS 2.0 or higher, on an 8088, 8086, 80286, 80386, or 80486
microprocessor.  On 386-based machines, it is most commonly used in
conjunction with Quarterdeck's 386 Expanded Memory Manager, QEMM-386, to form
a combination called DESQview 386.  You can run DESQview on a 386 without QEMM-
386, but you lose significant memory-management capability, ending up with an
environment virtually identical to DESQview on a 286, only faster.  Note that
DESQview and QEMM-386 are separate products which may be purchased separately,
and can be used together, or independently of one another.  For the reason
stated above, it is rare to find someone running DESQview on a 386 without
QEMM-386.  However, for reasons which will become clear, many people who do
not own DESQview buy and use QEMM-386 as their 386 Expanded Memory Manager of
choice.  In fact, we may wish to recommend QEMM-386 as a solution to TOPS/DOS
users on 386 machines who are having trouble running their applications in
conventional RAM.

QEMM-386 has two major functions:  First, it can transform a 386's standard
EXTENDED memory into EXPANDED memory (LIM EMS 4.0 and EEMS 3.2), which can
then be accessed by programs designed to take advantage of expanded memory, as
well as by DESQview, which can use it to create virtual DOS environments for
simultaneous operation of multiple programs.  Second, it can map RAM into
the unused addresses between 640K and 1MB (High RAM or UMBs) and allow
a user to load TSR modules (such as TOPS modules, for example) into it, thus
making more conventional RAM available to applications.  These two functions
are optional, and can be used independently of one another.

QEMM-386 consists of a device driver (QEMM386.SYS) many subsidiary programs
QEMM386.SYS is loaded from CONFIG.SYS with a command of the form:
DEVICE=[d:][path]QEMM386.SYS [options].  If QEMM386.SYS is installed,
DESQview, when launched, will recognize it, and take advantage of the services
it provides.  QEMM386.SYS works by using the 'virtual 8086' mode of the 386
microprocessor to provide such services as Expanded Memory Emulation.  It has
three possible 'states' in this regard - AUTO, ON and OFF.  AUTO means that
Expanded Memory will be available only when a program needs it.  ON means it
will always be available, and OFF means it is not available.  The default
state (which can be set as an option to QEMM386.SYS) is AUTO.  The current
state can be checked and set using QEMM.COM. The default state for Expanded
Memory Emulation is enabled.  To disable it, add the option FRAME=NONE to
QEMM.SYS.  Provision of High RAM is enabled by adding the option RAM to
QEMM386.SYS.  (Note that this forces the initial state to ON, and it cannot be
overridden.)  To load TSRs into this RAM, use the utility LOADHI.COM with a
command of the form:  LOADHI [d:][path]program.  There must be a contiguous
section of high memory that is large enough to load the TSR, or LOADHI.COM
returns an error and loads the TSR into conventional RAM.  You can get a map
of the first 1MB of RAM by entering the command QEMM without any parameters.
This will also return the current 'state' of QEMM-386 and the amount of
Expanded Memory, if any.

                     DESQview386 AND TOPS

I recently tested DESQview386 2.2 (as well as QEMM-386 4.2 as a stand-alone
memory manager) with TOPS/DOS 2.1 and NetPrint 2.0 on a Compaq386/20 with 2MB
RAM, VGA, and Compaq DOS 3.31.  Results were uniformly excellent on both
AppleTalk and Ethernet IF the basic rules of DesqView/QEMM/TOPS compatibility
are followed.

Rule #1:  Do not run DESQview on a TOPS Server.  There appears to be a basic
incompatibility between DESQview and TOPS' Server functionality.  This applies
not only to DESQview386, but also to DESQview on a 386 without QEMM- 386, as
well as to DESQview on a 286, 8086 or 8088.  It is fine to have the full
client/server software loaded, but if you have something published and someone
tries to access it, you will have problems.  Usually, both client and server
will eventually hang.  Note that I found no problem being a TOPS Server when
just QEMM-386 was loaded and active, unless DesqView was loaded as well.  I
did not test being a Print Server, but I would expect similar results.

Rule #2:  The LAP driver must have DMA set to none if QEMM-386 is loaded and
active ('state' is ON).  This is true in the case of ALAP and ELAP503,
although the symptoms using ALAP are much more dramatic.  If ALAP is set to
use DMA 1 or 3, and QEMM is ON, you will hang when you load TOPS or NetPrint.
If QEMM is AUTO, you will probably hang at some point after loading DESQview,
or otherwise accessing Expanded Memory from an application.  The problems seem
to take longer to develop when using ELAP503 with a DMA channel, but they were
unavoidable.  Since the default for ELAP503 is DMA=0, this will not normally
be a problem.  The rule of thumb is, if you are using QEMM-386, disable DMA.

Rule #3:  With DESQview, configure the LAP driver to use a software access
interrupt other than the default.  The default software access interrupt used
by all the TOPS LAP modules is 5C.  We suggest configuring the driver to use
some other interrupt, such as 60.  This can be most easily accomplished
through the "CONFIGURE" option in the SETUP program.

Rule #4:  Load TOPS and/or NetPrint BEFORE loading DESQview.  All TOPS and
NetPrint functions can be executed from within DESQview EXCEPT for the actual
loading of the memory resident modules.

When the above four rules were followed, all the TOPS network functions I
tried worked flawlessly.  I was able to see network servers and printers,
print to network devices, mount remote volumes, (and publish and act as a
server, if DESQview was not loaded), do bi-directional copying between two
machines, and run programs remotely, both from the command line in DOS with
QEMM.SYS on, as well as from DOS Windows in DesqView.  You can even create a
DESQview Program Information File for TOPSMENU and CONFIGUR, and run them in a
DESQview Window.  In one interesting experiment, I modified the Program
Information File for Microsoft Word 4.0 to run off drive D:, then I mounted a
Macintosh folder, copied the contents of my Word subdirectory into it,
launched Word remotely off the Mac drive, opened a Word document, edited it,
saved it, and printed through NetPrint, all from within DESQview with QEMM.SYS
active.  I was able to perform all these functions both with TOPS and NetPrint
loaded in conventional RAM, as well as when various TOPS and NetPrint modules
had been loaded into HIGH RAM with LOADHI.COM.

The same tests were performed with the previous version of DESQview, version
2.01, and its companion QEMM-386, version 4.1, with identical results, with
one exception.  If you try to load a TSR with LOADHI.COM, and there is
insufficient contiguous HIGH RAM available, LOADHI will inform you of the
fact, and load the program into conventional RAM.  If this occurred with a
TOPS module under QEMM-386 4.1, TOPS functions would no longer work. It was
necessary to LOADHI only those modules which would fit in HIGH RAM, and do a
conventional load on the others.  This problem did not occur with QEMM-386
4.2.

It is important to keep in mind that different architectures and designs are
employed in different 386-based machines.  This can sometimes result in
different behavior from TOPS with 386 Expanded Memory Managers on different
machines.  We have seen the exact same programs and configurations work on one
386 machine, and fail on another.  In general, reports from the field have
been uniformly positive regarding TOPS and DESQview386 when the above-
mentioned rules are followed.


  ************************************************************************
  *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) 1989-92 by Quarterdeck Office Systems          *
  ************************ E N D   O F   F I L E *************************