Zuse Z4 - Oldest Surviving Computer in the World - Lost in the archives

[K. Krause]

On 01.10.20 23:38, Eric Smith via cctalk wrote:It is going to need a lot 
of contact cleaning.
>> The one thing I like is the carry design the Zuse used. Really fast for
>> relays but not of much use for solid state.
>>
> Where is that circuit described?
The circuit is described in Konrad Zuses life memories. There is an english
translation available from the Springer publishing house.
Zuse used it's own logic symbols, which he named "abstrakte 
Schaltgliedlogik",
"abstract gating logic", because this logic could be applied to both, 
the full
mecanical Z1 and the later relais machines.
I found this carry logic built with transistors in a book from the early 
1960.
The author named it: killburn adder. It uses a chain of single transistors.

You can find a demonstration of the Zuse-adder on:
http://computermuseum.informatik.uni-stuttgart.de/virtuell/z1_adder.mp4
(sorry, it's in german only :-( )

Klemens