100 REM  DEVICE PRESENCE CHECKER
110 REM  BY PAUL G SAWYER
120 REM  STORE DEVICE # IN 252,
130 REM  SYS TO ROUTINE (49152),
140 REM  THEN PEEK(251). IF VALUE IS
150 REM  0 THEN DEVICE IS OFF,
160 REM  1 THEN DEVICE IS ON.
170 REM
180 REM  IF DEVICE CHECKED IS A DISK
190 REM  DRIVE, INITILIZE AFTER CALLING
200 REM  ROUTINE.
220 FOR I=49152 TO 49191:READ X:POKE I,X:NEXT
230 DATA 169,   0, 133, 251, 165, 252, 170, 160
240 DATA   0,  32, 186, 255, 169,   1, 166, 251
250 DATA 160,   0,  32, 189, 255,  32, 192, 255
260 DATA 165, 144,  72, 165, 252,  32, 195, 255
270 DATA 104,  48,   4, 169,   1, 133, 251,  96