Ferranti Mark 1

The Ferranti Mark 1, also known as the Manchester Electronic Computer in its sales literature, and thus sometimes called the Manchester Ferranti, was produced by British electrical engineering firm Ferranti Ltd. It was the world's first commercially available electronic general-purpose stored-program digital computer. Although preceded as a commercial digital computer by the BINAC and the Z4, the Z4 was electromechanical and lacked software programmability, while BINAC never operated successfully after delivery. The Ferranti Mark 1 was "the tidied up and commercialised version of the Manchester Mark I". The first machine was delivered to the Victoria University of Manchester in February 1951 (publicly demonstrated in July) ahead of the UNIVAC I which was delivered to the United States Census Bureau on 14 June 1951, having been sold on 31 March 1951. Based on the Manchester Mark 1, which was designed at the University of Manchester by Freddie Williams and Tom Kilburn, the machine was built by Ferranti of the United Kingdom. The main improvements over it were in the size of the primary and secondary storage, a faster multiplier, and additional instructions. Assembly of the computer began in the autumn of 1950 and lasted six months. The Mark 1 used a 20-bit word stored as a single line of dots of electric charges settled on the surface of a Williams tube display, each cathodic tube storing 64 lines of dots. Instructions were stored in a single word, while numbers were stored in two words. The main memory consisted of eight tubes, each storing one such page of 64 words.