I am a 35+ year veteran of Systems Programming, Systems Design and Architecture, Systems Administration, Store-and-Forward Messaging Systems, Realtime Control Systems, IPC before there were IPC APIs. Across such diverse platforms as DEC PDP, VAX; IBM 360 through 390, Series/1, System-3; NixDorf Datachecker; HP 2xxx/3xxx; 8088/8086/80286/80386 etc. powered systems.
Communications? BTAM, VTAM, Async, BiSync, TokenRing.
Languages? numerous Assembler, RALF/FLAP, Fortran, BASIC, PL/1, C, C++, COBOL; ksh/csh/bash, PERL, awk, CLIST, bat.

These lists are by no means complete, either; I know I have left out a few of each.

yeah -- I've been around a bit.