.plan

What this is

A .plan was a plain text file you left in your home directory. Anyone on the internet could read it by running finger against your address. Most people used theirs for “back at 3pm” notes. This was how you told people what you were doing, before there were blogs.

From 1996 onward, John Carmack used his as a working notebook. It starts as bug lists: a line for each thing fixed, a line for each thing still broken. Later it turns into something closer to a lab notebook.

All 394 surviving entries are collected here in order, one chapter per year. Each day carries a short note saying what it covers, so you can dip in anywhere rather than reading front to back.

Who wrote it

John Carmack co-founded id Software in 1991 and wrote the engines for Wolfenstein 3D, DOOM and Quake. Before those, real-time 3D needed a workstation. After them a PC would do.

He has released most of that code. Wolfenstein, DOOM, Quake, Quake II, Quake III and DOOM 3 are all public under the GPL, which is why DOOM has since been ported to cash registers and pregnancy tests.

The notes here run from 1996 to 2010. He wrote them for other programmers, and he leaves the dead ends in.

1. 1990Commander KeenAdaptive tile refresh, which got smooth scrolling out of EGA hardware
2. 1992Wolfenstein 3DRay casting, texture-mapped walls
3. 1993DOOMBSP trees, varying floor and ceiling heights, networked deathmatch
4. 1994DOOM II
5. 1996QuakePolygonal 3D, and client/server networking
6. 1997Quake IIOpenGL hardware acceleration, coloured lighting, game code in a C DLL
7. 1999Quake III ArenaCurved surfaces, a shader system, mods compiled to a portable virtual machine
8. 2000Founded Armadillo AerospaceLiquid-fuel rocket engines, built alongside the id work
9. 2004DOOM 3Unified per-pixel lighting, stencil shadow volumes
10. 2010The last .plan entryIt ends on “it works, and it was probably the right decision”
11. 2011RageMegatexture: unique texture data across a whole world, streamed from disk
12. 2013Became chief technology officer at OculusThe Rift, and the first consumer VR headsets
13. 2022Founded Keen Technologies, to work on artificial general intelligence

The years in gold are the years this book covers.

A page from it

How to read it