This is a web-based interface to nightly snapshots of the Plan 9 kernel from February 27, 1990 to March 25, 2003. The snapshots give an interesting view into the Plan 9 development process. Thanks to Lucent and kernel authors past and present for agreeing to publish the data. Through this interface, you can view any kernel source file as it existed at 5am New Jersey time on that date. The links above let you view and search the file list and the diff list. Below are some interesting file collections and dates. the power kernel (the original cpu server) the gnot kernel (the original terminal) the pc kernel February 27, 1990 the first snapshot November 21, 1990 replace ur-9P with what is now called 9P1. December 10, 1990 create the port directory June 25, 1991 beginnings of the PC (nee Safari) kernel July 5, 1991 new VM system November 15, 1991 add used-and-not-set checking to the compiler January 11, 1992 switch from error numbers to error strings May 1, 1993 switch from Plan 9 on bootes to Brazil on fornax August 4, 1995 add anonymous function arguments to the compiler February 1, 1997 switch file servers from fornax to emelie March 27, 1997 big cleanup. import IP stack from Inferno. first multiprocessor PC kernel. November 1, 1997 convert graphics model from bitblt to Inferno's color-mapped draw March 19, 1998 convert to 64-bit file offsets August 25, 1998 add printf-checking to the compiler March 23, 1999 allow spaces in file names June 29, 1999 add lexical file name dot-dot October 5, 1999 install true-color graphics support October 31, 1999 rename Brazil to Plan 9 December 30, 1999 correct handling of dotdot (add DEVDOTDOT) in device drivers May 27, 2001 install 9P2000 support January 15, 2002 remove 9P2000 transition code Over time the files changed their names a bit. The names of the diff files reflect the current names of the file but incorporate versions that used the old names. So for example, the file presented here as 1990/0227/sys/src/9/port/chan.c was really mips/chan.c at the time; it moved to port on 1990/1210. The true paths are in the raw data (available on the Plan 9 sources server), but not displayed here. I am slowly annotating all the diffs to explain their purpose, mark bug fixes, and so on, with an eventual goal of deriving interesting statistics about how operating system code in general and the Plan 9 kernel in particular evolves. If you are interested in helping to annotate, mail me. Please send comments and questions to Russ Cox (rsc@swtch.com). Enjoy!