Choosing the Host Operating System

There are two versions of MASM; one runs under DOS and the other under OS/2. Select the versions for the operating systems you use. If you want to run MASM under both DOS and OS/2, you can install both.

MASM can create executable files for OS/2 or DOS, regardless of which operating system the assembler runs under. Programs must be debugged and run under the operating system they were written for.