The introduction of the IBM flagship eServer zSeries 990 in May 2003 was just the most recent addition to a long line of the company's mainframe computers spanning more than 50 years. This is their story
The first general purpose automatic digital computer built by IBM dates back to 1944. It was an electromechanical machine developed in conjunction with Harvard University and was known as the Automatic Sequence Controlled Calculator. It performed additions in one-third of a second and multiplications in six seconds.
The Korean War sped the development of large-scale computers. In 1952, IBM announced its first fully electronic data processing system, the IBM 701 . The four years between the Selective Sequence Electronic Calculator and the 701 produced great advances in information technology. The 701 was only one-quarter the size of the SSEC and 25 times faster.
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