VAX Unix

Early in 1978, Professor Richard Fateman began looking for a machine with a larger address space on which he could continue his work on Macsyma (originally started on a PDP-10). The newly announced VAX-11/780 fulfilled the requirements and was available within budget. Fateman and thirteen other faculty members put together an NSF proposal that they combined with some departmental funds to purchase a VAX.

Initially the VAX ran DEC's operating system VMS, but the department had gotten used to the Unix environment and wanted to continue using it. So, shortly after the arrival of the VAX, Fateman obtained a copy of the 32/V port of Unix to the VAX by John Reiser and Tom London of Bell Labs.

Although 32/V provided a Version 7 Unix environment on the VAX, it did not take advantage of the virtual memory capability of the VAX hardware. Like its predecessors on the PDP-11, it was entirely a swap-based system. For the Macsyma group at Berkeley, the lack of virtual memory meant that the process address space was limited by the size of the physical memory, initially 1 megabyte on the new VAX.

To alleviate this problem, Fateman approached Professor Domenico Ferrari, a member of the systems faculty at Berkeley, to investigate the possibility of having his group write a virtual memory system for Unix. Ozalp Babaoglu, one of Ferrari's students, set about to find some way of implementing a working set paging system on the VAX; his task was complicated because the VAX lacked reference bits.

As Babaoglu neared the completion of his first cut at an implementation, he approached Bill Joy for some help in understanding the intricacies of the Unix kernel. Intrigued by Babaoglu's approach, Joy joined in helping to integrate the code into 32/V and then with the ensuing debugging.

Unfortunately, Berkeley had only a single VAX for both system development and general production use. Thus, for several weeks over the Christmas break, the tolerant user community alternately found themselves logging into 32/V and ``Virtual VAX/Unix.'' Often their work on the latter system would come to an abrupt halt, followed several minutes later by a 32/V login prompt. By January, 1979, most of the bugs had been worked out, and 32/V had been relegated to history.

Joy saw that the 32-bit VAX would soon make the 16-bit PDP-11 obsolete, and began to port the 2BSD software to the VAX. While Peter Kessler and I ported the Pascal system, Joy ported the editors ex and vi, the C shell, and the myriad other smaller programs from the 2BSD distribution. By the end of 1979, a complete distribution had been put together. This distribution included the virtual memory kernel, the standard 32/V utilities, and the additions from 2BSD. In December, 1979, Joy shipped the first of nearly a hundred copies of 3BSD, the first VAX distribution from Berkeley.

The final release from Bell Laboratories was 32/V; thereafter all Unix releases from AT&T, initially System III and later System V, were managed by a different group that emphasized stable commercial releases. With the commercialization of Unix, the researchers at Bell Laboratories were no longer able to act as a clearing-house for the ongoing Unix research. As the research community continued to modify the Unix system, it found that it needed an organization that could produce research releases. Because of its early involvement in Unix and its history of releasing Unix-based tools, Berkeley quickly stepped into the role previously provided by the Labs.