LEO (1950)

Amongst other references I found this In 1951 the LEO I computer was operational and ran the world's first regular routine office computer job. About the "Lyons Electronic Office" (LEO I) The LEO I used 5,936 valves, plus another 300-400 in auxiliary equipment. The LEO used 64 mercury tubes for storage (twice the memory capacity of the EDSAC machine built in Cambridge). Each memory tube was 5 feet, four inches in length and weighed half a ton. The computer was controlled from a control panel, with several oscilloscopes set up to monitor contents of the storage area. The machine also had a speaker installed and programmers could hear the sounds generated as LEO performed certain calculations. The programmers became so accustomed to certain frequency variations, that they could detect something was wrong with a program by the sounds produced through the speaker. The programmers also used this speaker arrangement to generate some of the first "computer music." Rod -----Original Message----- From: cctech-bounces at classiccmp.org [mailto:cctech-bounces at classiccmp.org] On Behalf Of Roger Holmes Sent: 18 July 2007 14:24 To: cctalk at classiccmp.org Subject: Re: LEO (1950) I suspect it is a contemporary promotional film on the Leo II dated 1957 and mentions that it has been working since 1953 - referring to Leo 1 I think, it is black and white and if that's it, I have it on a DVD published by Buzz KnowledgeWorks which I bought on eBay. I knew what you meant. Most early designs were one or two off scientific machines, price no object. I'm not sure many commercial machines were made with valves logic and a main memory of core. Transistors and core main memory often came in together. The ICT1200 series (AKA Hollerrith Electronic Computer) was drum main memory and valves but its replacement the ICT1300 series used "high speed switching transistors" and core memory with backing store of drum and optionally tape.