HP-41
The 1979 HP-41 series programmable calculator, produced until 1990, was famously used in the Space Shuttle missions. It featured an LCD alphanumeric display and was powered by a processor initially called "Coconut" (or 1LE3 CPU), later more broadly known as the Nut CPU. The calculator included RAM, ROM, and I/O capabilities, utilizing the interpreted programming language FOCAL ("Forty One Calculator Language"). Both the operating system and the interpreter were stored in ROM, programmed using the Coconut processor's assembly language, also called MCODE (or "M-Code"). A later upgrade, the NEWT Microprocessor, further enhanced its capabilities.