Simon Tatham's Home Page

Welcome to my web site. I'm Simon Tatham, a software engineer and free-software author in Cambridge, UK.

Here are links to the various other pages of this site.

• About me: some idea of who I am.
• Free software I've written, which you can download.
  • PuTTY: a Telnet and SSH client for Windows.
  • Halibut: a half-written documentation system which is used for the PuTTY manual.
  • DoIt: a utility to allow a Unix machine to open documents on a Windows machine (for example, sending commands back to your Windows desktop machine from a Unix server you've connected to from there).
  • WinURL: a Windows utility to pull text out of the clipboard and launch it as a URL at the touch of a hot-key.
  • Enigma: a block-pushing puzzle game. Originally invented by a friend; converted to a curses-based Unix game by me.
  • A collection of GUI puzzle games, portable to many platforms: provided on the web in Javascript and Java versions, downloadable versions for Windows, Unix and MacOS, and third-party ports to various mobile devices.
  • Tweak: a Unix curses-based hex editor designed for highly scalable performance.
  • IPBT: a Unix curses application which plays back ttyrec files with precision rewind capability.
  • A collection of miscellaneous Unix utilities.
  • agedu: a Unix utility for tracking down where you're wasting disk space, by making it easy to spot large amounts of data with last-access times a long time ago.
  • xtruss: an X11 protocol tracing utility.
  • spigot: a command-line exact real calculator.
  • Bitmap fonts and font utilities for Windows.
  • Gonville, an alternative font of musical symbols for use with GNU Lilypond.
  • A patch to bash(1) that implements a third mode of job termination notification.
  • ick-proxy, a disgusting utility for rewriting URLs in multiple web browsers.
• My algorithms collection: some neat algorithms that aren't in common use.
• Mathematical sorts of things. (Many of these pages include some downloadable software so you can play with them yourself.)
  • Filigrams: a kind of mathematical pretty picture, slightly similar to fractals but not exactly the same.
  • Newton-Raphson fractals.
  • Construction of polyhedra from mutually repelling points on a sphere.
  • Some pictures I've drawn on the surfaces of polyhedra, with downloadable nets so you can make your own copy.
  • A pair of dice which never roll 7.
  • A solution to the impossible Solitaire Army problem (by cheating, of course – making an infinite number of moves).
  • A couple of maths-themed HTML5 web toys, demonstrating Lagrange's polynomial interpolation formula and the Gauss-Lucas theorem.
• Articles, essays and things I've written.
  • How to Report Bugs Effectively: a general article on how to send a programmer a bug report which will actually help them fix the problem.
  • Coroutines in C: an implementation of Knuth's "coroutines" concept in portable ANSI C, by a similar technique to Duff's device plus some C preprocessor abuse.
  • Metaprogramming custom control structures in C: another piece of C preprocessor abuse to let you build quite general user-defined looping constructs alongside C's basic for and while.
  • Magic Aliases: a dirty trick you can do by combining aliases and shell functions in the Bourne shell.
  • The Infinity Machine: an exercise in what you might call "recreational computer science", inspired by Ian Stewart. Explores the potential consequences if an infinitely fast computer could be built (including defining precisely what that means).
  • The Descent to C: an introduction to C for people coming to it from higher-level languages, intended to warn you in advance about the likely culture shocks.
  • My experience of migrating to Subversion. Things to watch out for, things I'd do differently next time, things I'm glad I did the way I did.
  • My personal FAQ about the fact that I have no sense of smell.