10 REM FILE TEST
20 OPEN 1, 8, 4, "TESTFILE,SEQ,W"
30 IF ST <> 0 THEN PRINT "FILE ERROR"
40 IF ST = 0 THEN PRINT "FILE EXISTS"
50 CLOSE 1

ILLEGAL DEVICE NUMBER

ERROR: #9FL39L8LQN278LQ7XWZ9Q80JA8XK5V7P