Systems Software

What to expect

The history of operating systems, from the first batch loader for the IBM 704 in 1956, through the development of Unix to the launch of Windows and Mac OS.

Discover how the 360 mainframe nearly broke IBM, and how voice user interfaces (VUIs) are all the rage.

At MIT in the mid-1960s, work had stalled on the experimental operating system Multics, which was being designed for the General Electric mainframe. Bell Labs had pulled out of the project, frustrated by Multics complexity. Their researchers Ken Thompson and Dennis Ritchie embarked on a scaled down version on a PDP-7, initially calling it Unics, a pun on Multics. Bell Labs wanted to edit patent documents so Thompson and Ritchie ported the new OS to the much larger PDP-11 and added a word processor. The UNIX Programmer’s Manual was published on 3 November 1971, now considered “Unix’s official birthday”.

As he wrote utilities for the fledgeling OS, Ritchie was frustrated by the limitations of the programming language “B” so he wrote a new high-level language called “C” in 1972, and then rewrote the whole of the Unix operating system in C code in 1973. Unix was presented to the outside world at the 1973 Symposium on Operating Systems Principles, the same conference where six years earlier Larry Roberts had announced the ARPANET (see chapter 9). Unix proved hugely popular in academia, partly because it was so powerful.