Oldest operational computer

On Fri, 15 Feb 2008, William Donzelli wrote: Well, the types that I have listed are Noval/Miniature types and date from the fifties (the E180CC for example is the same as a 7062). These types were specifically made for computers and haven't existed during WW2 (where the development of Rimlock types had started at the end, but not Noval). According to your logic one has to call the E180CC an HiFi audio tube because everyone's using them as such nowadays. I think we have to differentiate between "computer tubes" as "tubes that were used in computers but not specifically made for computers" and "computer tubes" as "tubes specifically made for computers/digital applications". I am talking of the latter. Another example: The Zuse Z22 uses PL36 (or PL81?) for IIRC core memory drivers. This tube is actually a TV horizontal output tube and although extensively used in a computer, was definitely not a "computer tube". But the Z22 also uses logic modules with E92CC (7 pin dual triode, Green Series). Christian