Celebrating 50 years of Unix #Unix #Unix50 #History @belllabs

In the summer of 1969 computer scientists Ken Thompson and Dennis Ritchie created the first implementation of Unix with the goal of designing an elegant and economical operating system for a little-used PDP-7 minicomputer (serial number 34, info here) at Bell Labs. That modest project, however, would have a far-reaching legacy. Unix made large-scale networking of diverse computing systems — and the Internet — practical.

The Unix team went on to develop the C language, which brought an unprecedented combination of efficiency and expressiveness to programming. Both made computing more portable. Today, Linux, the most popular descendent of Unix, powers the vast majority of servers, and elements of Unix and Linux are found in most mobile devices. Meanwhile C++ remains one of the most widely used programming languages today. Unix may be a half-century old but its influence is only growing.

How Unix achieved success

In a 1973 at an ACM (Association of Computing Machinery) symposium, Dennis Ritchie described the Unix Time Sharing System:

UNIX is a general-purpose, multi-user, interactive operating system for the Digital Equipment Corporation PDP-II/40 and 11/45 computers. It offers a number of features seldom found even in larger operating systems, including:

A hierarchical file system incorporating demountable volumes,
Compatible file, device, and inter-process I/O,
The ability to initiate asynchronous processes,
System command language selectable on a per-user basis,
Over 100 subsystems including a dozen languages.

Ritchie credits the early success of Unix from ‘readability, modifiability, and portability of its software that in turn follows from its expression in high-level languages.’

But even more important than the visionary design was the sheer persistence of Ritchie and Thompson in keeping the project going, in an environment in which operating system research was not considered worthwhile. The team achieved a grass-roots success that made the system impossible to ignore. And because of the modest performance of the computers they used, they had to design the system to operate economically with limited memory and processor speed, which translated to very efficient performance later.

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