FDA (short for "first demo attempt"), also called first-try demo, is a type of a demo which depicts the player's very first attempt to play a map, without any prior knowledge about it. Players are expected to restart the map upon a death, and the demo lasts until the player completes the level or gives up. FDA demos are often used to give feedback to mappers, by showing them how a first-time player will experience the map.
The Doomworld forums host "first-try demo contests" where a new, never-before-seen map is published, and contestants try to record the fastest FDA demo of it.
FDA demos can be published at the Doomed Speed Demos Archive, though they aren't counted in the player's statistics.
Variants include the first exit which shows the first time a player managed to complete a map, and FRA ("first recording attempt"), a player's first stab at recording a demo on a map he's not yet fully familiar with.