Timer

Timer, otherwise known as, was a source modification made by programmer and speedrunner Andy Kempling (aurikan), with additional features by speedrunner Adam Hegyi. It is based on DOSDoom version 0.47.

Timer differs in scope from Kempling's other port, Chase, by being made for the TAS community. Together with, Timer became the basis for TASDoom.

Features
Taken directly from timer.txt

Timer has a few specific features that make it ideal for demo recordings: (Note: The features are only accessible in demo playback, to eliminate any chances of cheating.) - a precise on-screen timer with millisecond times (much like LMPC, but this can be viewed while watching the demo). With this timer, it's possible to time any demo's precise exit time, on both switch and teleport exit maps. - an on-screen monster counter, which displays the number of monsters alive. Lost souls are not counted as "monsters", because they don't count into the kills percentage. The icon thrower is not counted either, for the same reason. - a fast-forward/slow-motion feature. You can access this by pressing Z, X, C, V, or B. Z is slow-motion, X is normal speed, and C, V, B are fast-forward speeds. - a frag counter, which is visible when watching deathmatch recordings. It shows the frags of all players in the game. - an intermission timer similar to the on-screen timer. The meaning of the values at the bottom of the intermission are: Left value: (exiting time in gametics) mod 35 Right value: left value in milliseconds. So basically, put your demo time and the right value together, and you have your millisecond-precise time.

Legacy
Only one version of the port exists, simply named Timer. It is dated September 19, 2000. No source code or other versions are known to exist. With the existence of PrBoom+ as a demo recording tool, Timer has become pretty much deprecated.