CMD_CLEAR 
     CMD_READ 
     CMD_UPDATE 
     CMD_WRITE 
     TD_ADDCHANGEINT 
     TD_CHANGENUM 
     TD_CHANGESTATE 
     TD_EJECT 
     TD_FORMAT 
     TD_GETDRIVETYPE 
     TD_GETGEOMETRY 
     TD_GETNUMTRACKS 
     TD_MOTOR 
     TD_PROTSTATUS 
     TD_RAWREAD 
     TD_RAWWRITE 
     TD_REMCHANGEINT 
     TD_SEEK