n the 1950s and 60s giant mainframe computers gradually became a common sight in large companies - but it was not until the mid-70s that the idea of home computing started to take off.

... Programming in those days meant actually re-wiring boards...

Programmers of early 1950s computers, notably UNIVAC I and IBM 701, used machine language programs, that is, the first generation language (1GL).

The UNIVAC I (UNIVersal Automatic Computer I) was the first commercial computer produced in the United States.

ENIAC, short for Electronic Numerical Integrator And Computer,[1][2] was the first general-purpose electronic computer. It was a Turing-complete, digital computer capable of being reprogrammed to solve a full range of computing problems.[3] ENIAC was designed and built to calculate artillery firing tables for the U.S. Army's Ballistic Research Laboratory.

The ENIAC held immediate importance. When it was announced in 1946 it was heralded in the press as a "Giant Brain". It boasted speeds one thousand times faster than electro-mechanical machines, a leap in computing power that no single machine has since matched. This mathematical power, coupled with general-purpose programmability, excited scientists and industrialists. The inventors promoted the spread of these new ideas by teaching a series of lectures on computer architecture.

The ENIAC's design and construction were financed by the United States Army during World War II.

I well remember in 1964 working for IMI [ an offshoot of ICI ] where 'the computer' was something of which we were in awe , and we goggled at this huge building devoted to it , air conditioned , staffed by folk in white coats , and where no-one but its own staff had entry

I remember those days. The computer room was freezing cold because the machine gave off so much heat and had to be kept cool. You would see people working in coats even during the summer.

Its predecessor, which was programmed by rewiring was ENIAC