Return to "Visible Storage"

*** Please note: This website (comp-hist) was completed before I found out about Wikipedia in 2002.
Since then I have added material occasionally.
Items are certainly not complete, and may be inaccurate.
Your information, comments, corrections, etc. are eagerly requested.
Send e-mail to Ed Thelen. Please include the URL under discussion. Thank you ***


Manufacturer Zuse
Identification,ID Zuse-23
Date of first manufacture1961
Number produced 99
Estimated price or cost200,000 (DM) in 1961. Exchange rate then was about $1 = 4 (DM)
location in museum -
donor -

Contents of this page:




from The Z23 Computer
	a word length of 40 bits

Special features

Historical Notes
Konrad Zuse pioneered automatic computing in Germany is the late 1930s. Examples and restorations of early work are in Berlin and Munich Germany.
from - RE: starting my relay computer project

> From:
> Have you read "The Computer - My Life" by Konrad Zuse (New York: 
> Springer Verlag, 1993. ISBN 0-387-56453-5)? Mostly historical / 
> autobiographical, but some good technical bits on the evolution of relay 
> logic as Zuse's designs got more mature. Interesting how the number of 
> relays per bit he needed in his adder circuit got less and less...

from dwight elvey        24 Jan 2010
	I always loved his vertually zero delay carry. At least
	it was zero for relays. It was something that one
	would not think of just looking at a single bit or
	even normal logic of digital stuff.

This Artifact
Computer History Museum info Restoration of the Z-23

Interesting Web Sites

Other information

Message: 6
Date: Sat, 28 Aug 2010 10:17:46 +0200
From: Jochen Kunz 
Subject: Meet a Zuse Z23
Message-ID: <>
Content-Type: text/plain; charset=US-ASCII


This week I had the pleasure to visit a Zuse Z23 on display in my city.
The Z23 is a first generation, discrete transistor and diode logic, drum
based machine with a small "cache" of core memory. It is hosted at the
Fraunhofer Institute for Experimental Software Engineering. Here is the
Press release regarding the Zuse machine:

Ohh, if you can't read german (at all we are talking about a german
computer ;-) ) here is the english version:

I took some pictures:
The machine is in very good, but not working condition. I suspect it
would be a huge task to make it operable again, like the PDP-1
restoration. But it could be done. There is a complete set of
documentation, schematics, some spare parts, ... A former user of that
machine from the local university explained the machine and its inner
workings in detail to us. In one word: Fascinating! :-)

BTW: There is a tube based Zuse Z22 in working condition on display in
the ZKM museum in Karlsruhe (Germany). The Z23 is kind of a transistor
reimplementation of the Z22:
Pictures only in the german version:


If you have comments or suggestions, Send e-mail to Ed Thelen

Go to Antique Computer home page
Go to Visual Storage page
Go to top

Updated June 20, 2014