What is the history of the Basic Input Output System?

Answer 1

In 1973 Intel hired Gary Kildall on contract to write a PL/M compiler for their Intellec MDS-80 computer that they had just built to help their customers develop software for the Intel 8080microprocessor. While working on this compiler Kildall entirely on his own and without consulting Intel decided the computer needed an operating system, which he called CP/M. To make this operating system easier to write and facilitate porting to different 8080 based computers Kildall invented the concept of a BIOS, a ROM resident program providing bootstrap functions and low level hardware dependent I/O routines.

Kildall delivered all 3 products to Intel, but CP/M was rejected because Intel at the time decided they did not need operating systems as they were not selling computers; only microprocessor and memory chips. Kildall then started his own company called Digital Research to market CP/M. By 1976 Intel realized their mistake, but did not want to pay to license CP/M which they could have had for free earlier so they wrote their own operating system which they called ISIS.

Almost all microprocessor based computers since then have used a BIOS or something functionally equivalent.