The Unix Tree

Welcome to the Unix Tree. Here you can browse the source code and manuals of various old versions of Unix. For every file, you can also find related files from other versions: this can help show how the different versions of Unix are related. Most of the Unix versions below come from the Unix Archive.

Research Unix

These are the versions of Unix developed at Bell Laboratories, initially by Ken Thompson and Dennis Ritchie, later by many other of the researchers there.

Version	Date
First Edition Unix	1971-11
Second Edition Unix	1972-06
Third Edition Unix	1973-02
Fourth Edition Unix	1973-11
Fifth Edition Unix	1974-06
Sixth Edition Unix	1975-05
Seventh Edition Unix	1979-01
Addenda to 7th Edition	1980-12

USG/USL

Originally set up to support Unix internally, the Unix Support Group eventually became Unix System Laboratories, and developed the System III and System V commercial versions of Unix.

Version	Date
PWB/UNIX 1.0	1977-07
32V Unix	1979-05
System III	1980-06
PDP-11 3+2	1983-01

Other Early Unixes

As Unix was distributed non-commercially in the mid-1970s, many other institutions took the system and modified it. Many of the changes from these early variants were fed back into the research version of Unix.

Version	Date
Mini-Unix	1976-12
LSX	1976-??
Interdata 7/32 Port	1979-06
AUSAM	1979-10
V7M 2.1	1981-10

Early BSDs

The early BSDs, 1BSD and 2BSD, were collections of commands and libraries like the Pascal system, the ex editor and the C-shell. Later systems such as 2.8BSD through to 2.11BSD were complete, installable, 16-bit systems with kernel source.

Version	Date
The First BSD	1978-01
The Second BSD	1979-04
2.9BSD	1983-11
2.11BSD	1992-02

32-bit BSDs

3BSD was the first Unix to provide paged virtual memory. The 4BSDs went on to add features such as networking, the fast filesystem, vnodes & NFS, and they culminated in 4.4BSD-Lite which had been rewritten to contain no original Unix code.

Version	Date
3BSD	1980-03
4BSD	1980-10
4.1c BSD	1982-12
4.2BSD	1983-09
4.3BSD	1986-06
4.3BSD from UWisc	1987-01
4.3BSD Tahoe	1988-06
4.3BSD Reno	1990-06
The Net/2 Distribution	1991-06
4.4BSD	1993-06

Commercial Unixes

Many companies produced modified version of Unix, taking some or all of 32V, System III, System V, 4BSD, merging them and then value-adding to them.

Version	Date
Ultrix-11 3.1	1988-01

Unix Derivatives

Several systems started with Unix source code, but this was written out over time so that no original Unix code remains. The best known examples are OpenSolaris, FreeBSD, NetBSD and OpenBSD.

Version	Date
FreeBSD 5.3	2004-08
OpenBSD 4.6	2009-10
NetBSD 5.0.2	2010-02
OpenSolaris build 135	2010-03

Unix Clones

There have been many systems which implement the Unix system calls, library APIs and commands, but which did not include any original Unix source code. Here is a small selection.

Version	Date
Xinu	1987-01
Minix 1.1	1987-01
Minix 1.5	1989-11
Linux 0.96c	1992-07
Coherent 4.2	1994-12
Minix 2.0	1996-10
Linux 2.6.33.2	2010-04

Similarities between files are found using the ctcompare tool running in default mode. For each file, the list of similar files is given in descending order of the total number of similar token runs.