:retrocomputing: ret'-roh-k*m-pyoo'ting, n.
Refers to emulations of way-behind-the-state-of-the-art hardware or software, or implementations of never-was-state-of-the-art; esp. if such implementations are elaborate practical jokes and/or parodies, written mostly for hack value, of more ‘serious’ designs. Perhaps the most widely distributed retrocomputing utility was the pnch(6) or bcd(6) program on V7 and other early Unix versions, which would accept up to 80 characters of text argument and display the corresponding pattern in punched card code. Other well-known retrocomputing hacks have included the programming language INTERCAL, a JCL-emulating shell for Unix, the card-punch-emulating editor named 029, and various elaborate PDP-11 hardware emulators and RT-11 OS emulators written just to keep an old, sourceless Zork binary running.
— from The Jargon File