Hi Brian,
You wrote to Gregory Urban:
MH>GU>      Within the last month I finally took the plunge and rejected the
MH>GU> herd mentality by switching to OS/2 Warp 3.0.  Unfortunately I am 
having
MH>GU> a compatibility problem with LapLink version NU-2.01, it refuses to
MH>GU> communicate with my serial ports!
MH>That's right.  LapLink won't work under OS/2 (unless you have a native
MH>version).  Why?  Because OS/2 doesn't allow programs to
MH>controller the hardware ports...that's precisely how
MH>LapLink does it's business.  I've even had problems with
MH>LapLink in Win95 in a DOS box...it runs for a while then
MH>craps out.  WinNT would have the same limitation.
Then why have I been able to use my copy of LapLink (V4) reliably under
OS/2 in most cases. The only time I've had a problem was when I tried to
use it on someone elses system which had SIO installed. Under the
default COM.SYS I have no problems, and I've done some fairly large
transfers under OS/2.
Now there may be a problem with this dedicated version of LapLink, but
the generalisation is not valid in my experience.
MH>Why does OS/2 not let programs control hardware ports?
MH>Crash Protection.  If a program has completely control over
MH>a hardware port and it hangs on a call...it's locked the
MH>machine because it'll continue hammering that IRQ and
MH>nothing else will get service.  OS/2 intervenes in this
MH>case and tries to eliminate this problem.
But you _can_ allow OS/2 to give a program running in a DOS box full
direct access to the serial ports. Check your settings page.
I was amazed to find that my commercial software written for DOS,
using dual port memory in the DOS high memory area to communicate
with an intelligent serial controller and also directly accessing
the standard serial ports (including interrupt driven serial printing)
runs perfectly well in a DOS box under OS/2. As it is not OS/2 aware it
is hell on the rest of the system, but I suspect that by adding in code
to give up time slices in the keyboard handler (one place) it could be
made very OS/2 friendly. Re-writing it to move all the serial I/O to the
intelligent card would be somewhat more work, but would allow it to be
run under OS/2 without impacting significantly on the rest of the
system.
George
 * SLMR 2.1a * Desk: A very large wastebasket with drawers.
--- Maximus/2 3.01
---------------