Can random numbers replace serial numbers?

Steve Gaskill sgaskill at QNTM.COM
Tue Jun 3 16:26:30 PDT 1997

* From the SCSI Reflector (scsi at, posted by:
* sgaskill at (Steve Gaskill)
Pat ponders:

> On the third hand, for the purpose of such things as SCAM,
> I've sometimes wondered if something like a 64-bit random
> number would be, as a practical matter, indistinguishable
> from a distinct serial number.

If the device always returned the SAME random number then this might 
work pretty well...up until a collision occurs between two like 
devices.  If the random number was different each time the device 
powered up, the initiator might be unable to determine which device to 
boot from.  If you are lucky enough to boot, the O.S. may not be able 
to distinguish among like devices (two CD-ROM drives of the same 

Windows NT writes a signature on each disk drive so that it can figure 
out which drive is which, even after other drives have been added to 
or removed from the system.  However, this won't work on read-only 
devices or on removable devices with no media installed.

After all of the hype about SCAM (from the device people), I'm pretty 
disappointed that the operating system folks have yet to do anything 
with it.  For now it's just another buzzword on the marketing feature 


  steve gaskill
  sgaskill at

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