I came across a great book a few weekends ago, called A Computer Called LEO, that tells the story of the first computer to be used by business.
Its a particularly unusual story, because the idea for the computer in question emerged in the first half of the last century on the back of early management thinking (particularly scientific management) and the needs of Joseph Lyons and Co.'s expanding English tea shop empire in the 1920s (the McDonalds of its time in many ways).
The first LEO or ""Lyons Electronic Office" consisted of:
"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 LEO and later versions were eventually used by a number of large companies and government organisations in the UK and also in Australia, South Africa and Czechoslovakia.
But don't be put off by the hardware described above. There really are a number of interesting layers to this story, including innovation, information system design and even technology entrepreneurship. In fact this book really should be compulsory reading for anyone in the IT and consulting industry!
The LEO computer series was in operation between 1950s and mid-1970s but is far from forgotten and there is even a LEO Computer Society. I haven't read them but there have also been some early books looking at the history of the LEO: