Tony Harminc commented: <Tony> It's worth remembering that ASMH predates IFOX00. (Well, as far as customer availability goes; I have no idea what went on inside IBM.) I have never understood the point of IFOX00; it appears to be a reimplemention from scratch to the IEUASM specs, with a couple of trivial functional enhancements, and using reentrant code. Compared to IEUASM it has no significant performance advantage, appears not to exploit any particular aspects of virtual storage, the supported macro and assembler language is essentially identical, diagnostics are no better, and so on.
I can only guess at the internal politics in play at the time that must have led to this project, when ASMH already existed and offered so much more. IBM's usual internal competition, I suppose, but in such a small subject area... </Tony> As I remember, ASMH came out in 1971, IFOX in 1972. IFOX was the "official" assembler, while ASMH was an internal tool that was almost not announced (it took a lot of pressure from field SE's who insisted it made SYSGENs possible in an afternoon rather than a weekend with ASMF/IEUASM). So "internal politics" is correct -- some IBM execs apparently believed that PL/I would satisfy all future programming needs, and that Assembler applications would disappear shortly. IFOX actually had some internal improvements that helped performance: the second conditional-assembly and first final-assembly passes were merged, as had also been done in the Waterloo G assembler; both were based on ASMF. I doubt IFOX was a "from scratch" implementation. I gave a short talk on Assembler History at the San Francisco SHARE conference; look for the proceedings of session 12235. John Ehrman
