El Turco supports most features of the winboard protocol. The notable exceptions are the analyze command and pondering, which will be implemented in a future version. El Turco also supports crafty style opening books (.bin). The engine has a few command line options:
-t : Set the number of hashtable entries (default is 262144 entries which use 4MB RAM)
-r : Resign if El Turco's score reveals that the engine is more than a rook down