The last time I assembled for an x86 device was 1993. I have no experience with Turbo Assembler, so I can't really guide you. I know the version of Microsoft Assembler I was using probably didn't understand anything past 8086 instructions, so I would say don't use that one. But I doubt you could, seeing as how it had to be lifted from an 8" floppy...The only thing I can say is TASM is probably a good period-correct choice for your machine. They all produce executable code, so it's whatever your comfortable with. I just preferred the old MASM because you didn't have to define memory models and segment definitions, it by default only produced single-segment code.