This page is a collection of some keystones I found interesting in the computer hardware history.
1940 - 1950
ENIAC (1945) ENIAC was the first all electronic computer designed by John Mauchly and J. Presper Eckert at the University of Pennsylvania. It had 17000 vacuum tubs (rather than relays)
It had no memory for data or program, all numbers were kept in one of the computers' 20 accumulators, each could store 10 decimal digits.
It was built to perform complex ballistic calculation and was used to perform computations for the development of the hydrogen bomb.
There is a documentary called The Computers, which is about the women involved in it.
 The Computer Book