Here's an example of using AGMSSetSCSI to turn on the Quantum
Fireball's power down time delay feature, with a 30 second idle delay
before spinning down.  The hard drive is at SCSI ID 0.  The settings
are in page $0d: byte 1's low bit has to be turned on to enable this
feature.  The last four bytes specify the time delay in 10ths of a
second ($0000012C in hex equals 300 decimal).  Normally you don't have
to specify the device, but I have two hard drive controllers with
different device drivers.

AGMSSetSCSI device SCSI-Apollo.device 0 d 1/1 8/1 9/2c writecurrent

And this is the output it produces:

Using SCSI-Apollo.device unit 0 (ID 0, LUN 0), page $0d, "current" data source.
Received 24 mode sense bytes.  Raw mode sense data in hexadecimal:
 17 00 00 08 00 20 91 21 00 00 02 00 8d 0a 00 00
 00 00 00 00 00 00 00 00
Found page $0d, changeable, containing 10 bytes:
         00 01 02 03 04 05 06 07 08 09
         00 00 00 00 00 00 00 00 00 00
Now have 10 bytes of changed data for page $0d:
         00 01 00 00 00 00 00 00 01 2c
Writing to current data for page $0d...
Write successfully completed.