Device File specifications

[David Hattok]

Could someone please tell me the correct range of numbers that can be used in each of the fields of a device file? Are there any numbers that are excluded from use?

Instance number of the interface card c0 to ??
SCSI target address t0 to 15?
Device number d0 to 7?

[A. Clay Stephenson]

Hi David,
Believe it or not those cXtYdZ numbers mean absolutely nothing. They are for the benefit of us dumb humans. We could really set then to anything we like (e.g. 'MickeyMouse') and the device would function perfectly normal. The real issue and what the system cares about are the major and minor device numbers. The minor device number identifies the instance, scsi target, and LUN. Actually the limits you gave are correct. If you do an ioscan -fn and look for SCSI Interface you should see an 'ext bus' entry with an instance number just above. The instance number associated with the 'ext_bus' usually corresponds to the Cn number of the scsi controller. I say usually because someone could change the instance number but as long as the minor device number is correct everything would work just fine.

Man scsi_ctl,scsi,scsi_tape, etc. for details.

Hope this helps a bit, Clay

[A. Clay Stephenson]

Now David, for more practical advice; if you will do an ioscan -fn of your system and indicate the kind of device you are trying to attach, I think we can help you zero in on things.