Re: about computer designs

[Brian Reid <reid>]

I am very dubious that Leitz (or anybody else) could have had a Z4
computer for lens design. According to John A. N. Lee, computer
historian at Virginia Tech, only one Z4 was ever built and it stayed
at ETH in Zurich. Here's what he has to say about it:

   During 1936 to 1938 Konrad Zuse developed and built the
   first binary digital computer in the world (Z1). A copy of
   this computer is on display in the Museum for Transport and
   Technology ("Museum fur Verkehr und Technik") (since 1989)
   in Berlin. 
   
   The first fully functional program-controlled
   electromechanical digital computer in the world (the Z3)
   was completed by Zuse in 1941, but was destroyed in 1944
   during the war. Because of its historical importance, a
   copy was made in 1960 and put on display in the German
   Museum ("Deutsches Museum") in Munich. 
   
   Next came the more sophisticated Z4, which was the only
   Zuse Z-machine to survive the war. The Z4 was almost
   complete when, due to continued air raids, it was moved
   from Berlin to Gottingen where it was installed in the
   laboratory of the Aerodynamische Versuchanstalt
   (DVL/Experimental Aerodynamics Institute). It was only
   there for a few weeks before Gottingen was in danger of
   being captured and the machine was once again moved to a
   small village "Hinterstein" in the Allgau/Bavaria. Finally
   it was taken to Switzerland where it was installed in the
   ETH (Federal Polytechnical Institute/"Eidgenossisch
   Technische Hochschule") in Zurich in 1950. It was used in
   the Institute of Applied Mathematics at the ETH until 1955. 


My German is pretty rusty, but if yours isn't, the full explanation of the
disposition of this one and only Z4 is contained in
    http://www.access.ch/zopfi/ZuseZ4.html 
as I struggle through reading it in German it looks to me as though the
machine stayed in Zurich until 1955 when it was decommissioned and moved to 
Munich.

Perhaps Leitz sent people from Wetzlar to Zurich to use this machine. It
would have been the fastest computer on the continent at that time.