"codex - coding/decoding algorithm...
IA - information architecture
raw - not yet coded...
this reads like some white paper from the more demented "Enterprise Architecture" IT goblins!"
Codex = Army book.
IA = Imperial Armour - stuff produced by ForgeWorld (FW)
RAW = Rules As Written. As opposed to RAI (Rules As Intended). Which you of all people will realise are two very different things.