My first was an S100-based Z80 system (with 64K of RAM) and dual 8" floppies, running CP/M. And a Heathkit H19 terminal, lovingly hand-soldered. Ran the BDS C compiler, and the Mince (Mince Is Not Complete Emacs) editor. I got 2 1/2 years of use out of it before getting the first IBM PC.