Dec 122017
Borland tech note on use of their products under DOS 5.
File DOS5_BOR.ZIP from The Programmer’s Corner in
Category Tutorials + Patches
Borland tech note on use of their products under DOS 5.
File Name File Size Zip Size Zip Type
DOS5.TXT 5876 2591 deflated

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Contents of the DOS5.TXT file

DOS 5.0 and Borland Language Products

DOS 5 brings a new level of memory management technology to PC's. Along with
this new technology comes a higher degree of technical complexity, requiring
more knowledge in making DOS 5 work with pre-dos 5 software and hardware.
Fortunately, most DOS 5 issues are easily solved.

The shipping versions of our C/C++ language products and Turbo Debugger
& Tools are essentially compatible with DOS 5. There are, however,
several issues one needs to be aware of when using protected mode versions
of our products in conjunction with DOS 5.


To make DOS 5 and EMM386 work properly with BCX and the other products
listed above, you need to use emm386.sys in the following fashion --

device = dos\emm386.exe ram XXXX

where XXXX is the amount of EMS to allocate. There seems to be an
approximate 1-1 correlation between EMS allocated and extended memory
available to BCX, so a value >= 800K for EMS would be appropriate.
Basically, we are "reserving" memory for use by TKERNEL which is
Borland's DOS extender kernel, loaded automatically by BCX, BCCX,
TLINKX, and TD286. Specifying 'ram 64' can cause a system reboot, and
'ram 256' will produce an insufficient memory error similar to the
one below :

System: Insufficient Memory To Load Task
Error : Cannot Create Task

The 'frame=none' option doesn't solve any problems, giving errors
when EMSTEST is run and causing a reboot when File|Get Info is selected
when running BCX. It isn't really advisable to use 'frame=none' with
our products.

Note that tests used EMM386 in conjunction with himem.sys and "dos=high,umb"

TD386, TF386

TD386 versions prior to 2.51 will not operate properly with DOS 5. If you
have version 2.0+ of Turbo Debugger, TD386 2.51 is available on our
download BBS (408.438.9181) as well as on Compuserve and BIX. The filename
for the download BBS is "TD386.ZIP." If you have a version of Turbo Debugger
prior to 2.0, you'll need to upgrade to the latest version.

TD386 2.51 will not work with DOS 5.0 when either EMM386 or DOS=HIGH is
used in config.sys. EMM386 puts the processor into V86 (virtual-86)
mode and poses the same problem as QEMM or 386-to-the-Max in that
TDH386 needs to control the processor.

DOS=HIGH causes another unexplained problem that Borland is currently
investigating. The problem is manifested by TD386 appearing to load
and then failing to load all the way, causing the computer to lock up.

TF386 on some systems causes the computer to lock up when you load an app
and then hit Alt-X to quit. The causes of this behaviour are still being
investigated. For now, test TF386 on your system for compatibility. If
you have a problem, report it to Borland through our online services
(Compuserve, BIX, and Genie) or though technical suport (408.438.5300).


MAKE has been reported to hang on some systems with DOS 5.0 using the
.SWAP directive within MAKE. Removing the .SWAP has solved the problem
on all systems reporting difficulties.


When you are using EMM386, Windows will no longer work in Standard Mode, thus
preventing a person from running BCX and Windows simultaneously. However,
if you use QEMM-386 (a memory management product from Quarterdeck Software),
you can run Windows in Standard mode without a problem, thus gaining
signficant flexibility. QEMM-386 will also work with "dos=high"
and "devicehigh" without any apparent problems. QEMM-386 also seems to be
more efficient than EMM386 in loading resident programs up into upper memory
blocks as well as offering more options for custom configuration. Furthermore,
QEMM-386 takes approximately 7K less memory below 640K than DOS 5's
HIMEM/EMM386 combination. For many uses, QEMM offers a superior solution
to memory management rather than using DOS 5's HIMEM and EMM386 utilities.

DOS 5.0 and Windows 386 Enhanced Mode and BC++

DOS 5.0 includes the ability to load device drivers and TSR's above 640K
to free up more memory to applications. This ability is very useful under
Windows 3.0 when running BC++ (BC.EXE) in 386 Enhanced mode. Under DOS 5.0,
you can achieve a DOS box with 600K+ of available memory which can
dramatically speed up BC++ compile/link times, approaching BCX compile/link
times for small to medium input files. The overall strategy for those
people running BC++ under 386 Enhanced Windows is to maximize the amount of
memory available in a DOS box so that BC++ will have more memory to work
with before it has to swap to EMS or to disk. Be sure to "lock" your
application and EMS memory in your PIF file, just as before DOS 5.0.

Other Incompatibilities

DOS 5 has been reported to cause conflicts with certain mouse drivers,
device drivers, BIOS versions, and TSR's. Many times a perceived problem
with Borland products is not due to a direct incompatibility but a side
effect of an incompatibility with another product. When trying to
determine if there is an incompatibility between your system, DOS 5, and our
products, try booting with a config.sys and autoexec.bat similar to
those shown below:


path =
prompt $p $g


With DOS 5 comes a higher degree of technical complexity in configuring one's
computer system(s) for optimal operation. Borland is committed to ensuring
that our software works with DOS 5 and we will provide whatever is needed to
customers so that they can utilize the advantageous features of DOS 5.

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