4 ms·

HP11C calculator (1981) might be the oldest. I occasionally use it for a quick calc just because. HP16C of similar vintage also. edit: And an HP71B (1984) wh

by cagey 4y ago

HP11C calculator (1981) might be the oldest. I occasionally use it for a quick calc just because. HP16C of similar vintage also. edit: And an HP71B (1984) which is definitely programmable (assembly and BASIC; I don't have the FORTH module).