Old-school mainframe programmer, specializing in system tools. z/OS, z/VSE, z/VM, a bit of Linux on z, and from the non-IBM world, BS2000/OSD and MSP. My expertise is IBM z/Architecture assembler and C, with REXX, COBOL, PL/I, and (ugh) CLIST as other strong suits.
Would like to learn/play with other OSes...if I could only have the time.