The Bell Laboratory in Murray Hill, NJ was also a very special place, although for different reasons. Bell Labs in the sixties had already a distinguished record for advancements in technology, with breakthroughs such as the transistor or the first data networks. Today, Unix (together with the C language) is considered among the ten top innovations from Bell Labs. His origin however was quite humble.
A few years before, in 1964, Bell Labs had joined MIT (Massachusetts Institute of Technology) and General Electric on an ambitious project to develop a new time-sharing operating system, called Multics. Multics introduced several new revolutionary concepts: hierarchical file system, security, virtual memory, online reconfiguration among others. In despite of this, and concerned with slow progress and increasing complexity, Bell Labs began to withdrew from the project in 1969. Ken Thompson, Dennis Ritchie and others realised they would be soon without a project or machine to work on, but they were full of ideas. They wanted to implement some of the cooler concepts of Multics, but this time to keep it simple. So they started to lobby for a new machine, with no luck, until Ken found the famous little-used PDP-7 computer sitting on a corner.
The "Space Travel" game was the first program ported to this machine, followed by a filesystem that Ken had designed on paper and that would be the base for the new operating system. Soon followed a small kernel, the shell and user-level utilities. Everything had to be written assembler on a GE-635 machine and transferred on paper tapes to the PDP-7, until an assembler was written and the system was able to support itself. The foundations of Unix were laid, but it was only in 1970 that the name Unix was coined, reportedly by Brian Kernighan, as a pun on Multics.
PDP-7 Unix had several interesting differences compared to subsequent versions of Unix. The interested reader can check Dennis Ritchie's paper, The Evolution of the Unix Time-sharing System, on Dennis Bell Labs home page (see Links section). With a working OS in place, another proposal was made to purchase a new machine, and a brand new PDP-11 came on May, 1970. One of the earliest programs ported was the roff text formatting tool, which the Patent department began using for patent applications in 1971. Unix was being useful and successful, more hardware was acquired and development continued. The third Unix version incorporated multiprogramming. The fourth release was rewritten in the C language. Shell scripting, redirection, pipes, job control, and several compilers such as Fortran were available at this point. Versions 5 and 6 appeared in 1975, and at this point, and due to regulations that prohibited Bell from selling software, the OS began to be distributed in source code to several universities. A new era began for Unix, and this will be covered on next article.
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