Computer firm IBM made technological history on 12 August 1981 with the announcement of a personal computer – the IBM 5150. Costing $1,565, the 5150 had just 16K of memory – scarcely more than a couple of modest e-mails worth. The machine had an “open architecture” which meant other firms could produce compatible machines. IBM banked on being able to charge a license for using the BIOS – the software which controls the heart of the machine.

The first 8086 processor took two engineers three weeks to design, and most modern CPUs are based on it.

Read more: BBC News