See also NOTICE and LICENSE in this directory.

A fairly complete history of the Plan 9 kernel is now available at
/n/sources/contrib/9hist.tar.gz, which is also unpacked for browsing
in /n/sources/contrib/9hist.  The data may be of interest to people
studying the evolution of software.

Each file (e.g., 9hist/carrera/main.c) is stored as a sequence of ed
scripts that can be run to create successive versions of the file over
time.  The show and showdiff scripts let you inspect a particular
file's history.  For example,

   cd /n/sources/contrib/9hist
   show carrera/main.c
   showdiff carrera/main.c 1999/1031
   show carrera/main.c 1999/1031
   showdiff carrera/main.c

There is a web version of the data at http://swtch.com/plan9history.
Aside from being GUIer, the presentation there is annotated with
comments about the various changes.

Thanks to Lucent and kernel authors past and present for agreeing to
publish the data.

Over time the files changed their names a bit.  The names of the
diff files reflect the current names of the file but include diffs against
the old names.  The major name changes are:

	before 1990/1210, "/sys/src/9/port" is really /sys/src/9/mips
	before 1991/0201:
		"/sys/src/9/power" is really /sys/src/9/mips
		"/sys/src/9/gnot" is really /sys/src/9/68020
	before 1992/0808, "/sys/src/9/pc" is really /sys/src/9/safari
	from 1993/0501 to 1999/1031, "/sys/src/9" is really /sys/src/brazil

The "## diff" comments in the diff files always show the true names.

Please send comments or questions to Russ Cox <rsc@swtch.com>.