XT vs AT I/O question

[S. Tom Strange]

 Here' s an interesting problem we have run into regarding running
 executable programs on an IBM PC-XT, a Compaq Plus, and an IBM PC-AT.

 We have written all of our code using Lattice C Version 2.15A.  Its
 practically a brand new version so this may be a bug with the new version.

 When our code is compiled and linked on the XT we are able to run it
 properly on the XT, the AT and the Compaq.  ( The XT has 640K and an 8087,
 the Compaq has 512K and an 8087, and the AT has 512K and the 80287 ).

 When the code is compiled and linked on the Compaq, it will run fine on the
 Compaq and the XT, but not on the AT.  The problems seem to be encountered
 using the "putch" and "getch" functions.  The "raw mode" seems not to be
 working.  Instead, the characters are echoed to the screen, and not
 recognized by the program until a return is typed.

 We tried relinking our object modules that were compiled on the Compaq
 on the XT and the AT.  We worked fine on the XT, but had the same problem
 on the AT.

 There is the possiblity that Lattice misspoke itself when they said 
 what a putch and a getch did because we are using their definition
 as stated in conio.c for the bdos calls.  I would guess that it may
 be an inconsistency between PC-DOS 2.0 and 3.0 except that our previous
 versions compiled and linked on the XT worked on the AT.

 Please respond to me by email.  I will post a sumary of the
 responses to the net.

 Tom Strange
-----
gangue!tom  (Tom Strange) at MINEsoft, Ltd.
...ucbvax!nbires!gangue!tom
-- 
gangue!tom  (Tom Strange) at MINEsoft, Ltd.
...ucbvax!nbires!gangue!tom