Micro Code

Michael's blog about teaching, hardware, software and the things inbetween

Zuse Z23 at RRZE Erlangen

October 22, 2017 — Michael Engel

Tonight was the Long Night of Science in the Erlangen-Nuremberg-Fuerth metropolitan area. The computer science department of Erlangen Uni had a large number of interesting talks, exhibits and demos. Most fascinating was the live demo of the computing centre's (RRZE) Zuse Z23 machine, which they have painstakingly restored to working condition over the last few years.

The machine successfully checksummed and booted its OS and was able to execute some applications loaded from paper tape -- a program to calculate pi and another one playing music by rhythmically accessing the magnetic drum. Very nice! :)

The OS (Grundprogramm = basic program) source code is about 1000 lines of assembler, see a printout at the museum of Kaiserslautern University:

Z23 OS source code

Some impressions:

The machine Another view of the Z23 Z23 console Z23 core memory Z23 logic module

The logic module is a "negator" (inverter) TS701a, see the schematic here:

Z23 negator schematic

Tags: Zuse, Z23, retro