First generation of vacuum tubes

Answer 1

The first generation of computers is said by some to have started in 1946 with ENIAC, the first 'computer' to use electronic valves (ie. vacuum tubes). Others would say it started in May 1949 with the introduction of EDSAC, the first stored program computer. Whichever, the distinguishing feature of the first generation computers was the use of electronic valves.

My personal take on this is that ENIAC was the World's first electronic calculator and that the era of the first generation computers began in 1946 because that was the year when people consciously set out to build stored program computers (many won't agree, and I don't intend to debate it). The first past the post, as it were, was the EDSAC in 1949. The period closed about 1958 with the introduction of transistors and the general adoption of ferrite core memories.

OECD figures indicate that by the end of 1958 about 2,500 first generation computers were installed world-wide. (Compare this with the number of PCs shipped world-wide in 1997, quoted as 82 million by Dataquest).

Two key events took place in the summer of 1946 at the Moore School of Electrical Engineering at the University of Pennsylvania. One was the completion of the ENIAC. The other was the delivery of a course of lectures on "The Theory and Techniques of Electronic Digital Computers". In particular, they described the need to store the instructions to manipulate data in the computer along with the data. The design features worked out by John von Neumann and his colleagues and described in these lectures laid the foundation for the development of the first generation of computers. That just left the technical problems!

One of the projects to commence in 1946 was the construction of the IAS computer at the Institute of Advanced Study at Princeton. The IAS computer used a random access electrostatic storage system and parallel binary arithmetic. It was very fast when compared with the delay line computers, with their sequential memories and serial arithmetic.

The Princeton group was liberal with information about their computer and before long many universities around the world were building their own, close copies. One of these was the SILLIAC at Sydney University in Australia.