SCAM and boot devices

Lohmeyer, John JLOHMEYE at
Tue Feb 13 14:27:00 PST 1996

* From the SCSI Reflector, posted by:
* "Lohmeyer, John" <JLOHMEYE at>

Eddie Williams wrote:
>This only helps for disks.  What about tapes, CDs, printers, etc?  Writing
>to the wrong tape could cause some serious problems too.

I assume your point is that a system with multiple tape drives could get 
confused about which drive is which.  The industry has always had a similar 
problem in that operators don't always mount tapes on the correct tape 
drive.  I maintain that the best solution is to use volume labels on tapes 
too.  However, this gets done more often on mainframes than on PCs.

There is another effort going on in the industry that may help:  Globally 
unique device identifications.  X3T10 recently added a Device Identification 
Vital Product Data page to the SCSI-3 Primary Commands (SPC) draft standard 
that allows SCSI devices (parallel or serial) to report their globally 
unique identification(s).  This will permit the operating systems to 
identify all of their peripheral devices after SCAM or a serial protocol 
scrambles their physical addresses.

I expect that most peripheral devices will have globally-unique 
identifications.  This is especially useful on larger systems that may have 
redundant paths to I/O devices.

>Ed.Williams at ColumbiaSC.NCR.COM

It sure is nice to see resurrected...

John Lohmeyer             E-Mail:  john.lohmeyer at
Symbios Logic Inc.         Voice:  719-573-3362
1635 Aeroplaza Dr.           Fax:  719-573-3037
Colo Spgs, CO 80916     SCSI BBS:  719-574-0424 300--14400 baud

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