x86 Assembler Recommendations

[Michael B. Brutman]

I'm trying to learn device driver programming, the target being a PCjr. 
  (If you know the PCjr, you know it needs a lot of help from device 
drivers.)  Eventually I want to start patching the BIOs, but for now 
I'll live with device drivers.

Microsoft MASM 5.x looks to be a reasonable choice, except it is hard to 
find.  Borland TASM would also work, but I'm not sure what version I'm 
looking for.  A 'good' version would be compatible with MASM 5.x and 
still run on my 386 based PC, which is the development box.  (MASM 6.xx 
is out of the running because it doesn't run in pure DOS.)

Any recommendations?  Any leads on where to find one of these reasonably 
priced?


Regards,
Mike