bob@nbires.UUCP (Bob Bruck) (05/30/85)
*** REPLACE THIS LINE WITH YOUR INCOMPATIBILITIES *** I recently formatted my fixed drives using PC-DOS 3.0, knowing at the time that the format of the partitions would be different than with PC-DOS 2.x (sectors reserved for ROOT directory, etc). What I did not realize was that PC-DOS 2.x would no longer run using DOS partitions formatted by 3.0 because it has the disk format hard coded into IBMBIO.COM based on the par- tition size rather than read from the boot sector. I also was not aware of the incompatibilities between DOS 2.x and DOS 3.x. This meant that 1) pro- grams that check for the DOS version being "2" and 2) programs that do funny things with BAT files would not work on my machine! The first problem was easy to solve. I use DEBUG to find the code that checks for the DOS version number (MOV AH,30; INT 21) and patch the code to work with DOS 2.0 or greater. I also have a resident kludge program that I run to tell the programs being run that they are running DOS 2.11 (it lies). The second problem had me stumped for a while. I finally tried running PC-DOS 2.11 COMMAND.COM on my (by now) DOS 3.10 machines and it worked! All of the programs that I was not able to run under 3.x seemed to work perfectly. My question is this. What kinds of compatibility problems have other people had running DOS 3.x (that I can expect to have in the future), and what problems am I going to have running COMMAND.COM from 2.11 under 3.x? Also, what did Microsoft (IBM?) do to COMMAND.COM to create these incompatibilities? Would running 2.11 COMMAND.COM on a PC-AT allow it to run software that could not otherwise run on an AT? Bob Bruck (hao,allegra,ucbvax)|nbires|bob