Simtel MSDOS 1992 June/SIMTEL_0692.cdr/msdos/desqview/xdvee11.arc/XDVEE.DOC

Text File | 1989-06-06 | 4KB | 71 lines

XDVEE COPYRIGHT 1988-1989 JOHN NAVAS II, ALL RIGHTS RESERVED.

XDVEE is made available for personal, non-commercial use only.  You
are granted a limited license to use XDVEE, and to copy it and
distribute it, provided that no fee is charged for such copying and
distribution, and that it is ONLY distributed in its original,
unmodified state.  XDVEE is distributed AS IS, without warranty.

XDVEE is designed to overcome the weakness in AST REMM.SYS 4.2 (a copy
of which is included) that causes the AST Premium/286 to lock-up when
communications are running under DESQview(tm) Version 2.  The problem
is described in the accompanying file REMMSYS.BUG, which was
downloaded from the AST Tech Support Bulletin Board (714-852-1872).

Why use REMM.SYS 4.2 at all?  Why not simply use REMM.SYS 3.5 (as AST
and Quarterdeck suggest)?  The answers are: (1) that you may be
running software other than DESQview that requires EMS 4.0 support
(such as Microsoft Excel for Windows) which only REMM.SYS 4.2
provides; and/or (2) that REMM.SYS 4.2 permits larger windows than
REMM.SYS 3.5 in certain configurations!

XDVEE is provided in two versions.  The basic version, XDVEE, gives
about the same window size with REMM.SYS 4.2 as REMM.SYS 3.5, and is
the safest since it completely hides EMS 4.0 functions from DESQview.
In some configurations, the alternate version, XDVEE1, makes possible
a larger window (40K larger on a DESQview 2.2 VGA test configuration)
by letting XDV.COM allocate memory with EMS 4.0 functions, but may be
riskier due to the difference in EMS functions available to XDV.com
and DV.EXE (although it has been tested successfully).

For best results, it is important to install REMM.SYS 4.2 correctly
in your CONFIG.SYS file:
1.  By default, REMM.SYS 4.2 reserves 255 Process ID's (EMS handles),
which is wasteful of memory unless such a large number is needed.  I
recommend /P=32 (which is the same as the default in REMM.SYS 3.5).
2.  It's a good idea to exclude whatever memory space is required by
your video card with the /X= option.  A common problem is that some
VGA cards "lie" about how much ROM memory they have.  16-bit VGA
cards usually requires the entire range from A000h to C7FFh.
3.  The /S= option should not be used with XDVEE.  On the other hand,
if you don't have any ROM in the E000h bank, it is possible to
place the EMS page frame there, which may give larger windows using
XDVEE1.
   For example, with REMM.SYS located in the C:\DOS directory and a
16-bit VGA video card using XDVEE:
   DEVICE=C:\DOS\REMM.SYS /X=A000-C7FF /P=32
and using XDVEE1:
   DEVICE=C:\DOS\REMM.SYS /X=A000-C7FF /P=32 /S=E000

To use XDVEE (or XDVEE1), simply copy it to your DESQview directory.
Then, instead of executing XDV or DV, execute XDVEE (or XDVEE1).
XDVEE (or XDVEE1) will in turn execute XDV.COM, which must be present
in your DESQview directory.  IN OTHER WORDS, DO NOT RENAME XDV.COM TO
DV.COM!  Tip:  To see how XDV.COM allocates memory for XDV.EXE, use
the /L command line switch; e.g. XDVEE /L or XDVEE1 /L.

XDVEE works by installing itself as a filter for INT 67h, pretending
to be an EMS driver, spawning XDV.COM (passing all command-line
arguments), and limiting DV.EXE to EEMS functions.
    If ALLOW1 is not defined, it converts any Get EMS Version
(Function 46h) response > 3.9 to 3.9 (the version returned by AST
REMM.SYS 3.5); XDV.COM and DV.EXE are thereby fooled into using EEMS
(instead of EMS 4.0) functions.  (XDVEE.COM.)
    If ALLOW1 is defined, it does not interfere with the first (and
only the first) Get EMS Version (Function 46h) response; this lets
XDV.COM allocate memory using EMS 4.0 functions, while still fooling
DV.EXE into using EEMS functions.  (XDVEE1.COM.)

DESQview is a trademark of Quarterdeck Office Systems (Tech Support
BBS: 213-396-3904).