Don’t you love a graph with a logarithmic axis? Here’s one showing the installed life of each generation, with a couple of exponential fits:
Between 1958 and 1970 (end of the data) the annual growth rate of new computers was 34%. After the first year, installations decline at a rate of around 16% per year (presumably replaced by a more powerful system).
Also
The table below shows the six computer models, out of 48, that represented 60% of all computers installed. The monthly rentals are an estimated average, and inflation adjusted 2026 pounds sterling. Possible memory capacities varied between 4k to 64k (yes, thousands of bytes). Readers will be familiar with the IBM 360, the ICL 1900 series was the UK’s home-grown response (via Canada):
Computer Installed Percent Monthly rental IBM 360/30 305 17 £42k ICL 1901 253 14 £21k IBM 360/20 147 8 £17k ICL 1902 138 8 £37k IBM 360/40 127 7 £84k ICL 1903 101 6 £45k
Here’s the article
See also
The Birth of the British Computer Industry
1961, Number of Computers Per Million Persons(*)
