Not that I'm a fan of C but I'm surprised just about none of the comments have mentioned metal C, especially when there are comments directed towards using some of the assembler-only interfaces and thus challenging how to use those in C..
<snip> But there is a substantial portion written in HLASM which would not be written in PL/X. Writing those in PL/X would have make MVS unmaintainable. </snip> The second sentence is untrue, unless you're thinking of some product like JES which historically has made its source available for customer modification. Peter Relson z/OS Core Technology Design
