SSC Large Addresses

Ralph Weber ralphoweber at CompuServe.COM
Mon Feb 28 07:45:07 PST 2000

* From the T10 Reflector (t10 at, posted by:
* Ralph Weber <ralphoweber at>
The ugly thing about adding a Service Action code is
that the TCLP, LONG, and BT bits occupy the place where
Service Action codes go.  You can turn the current
TCLP, LONG, and BT bits (plus bits 3 and 4 of byte 1)
into a Service Action code, but you can't start with
zero meaning "the old way."  Rather, you've got something

Code        Description
00h         TCLP=0, LONG=0, and BT=0 today
01h         TCLP=0, LONG=0, and BT=1 today
02h         TCLP=0, LONG=1, and BT=0 today
03h         TCLP=0, LONG=1, and BT=1 today
04h         TCLP=1, LONG=0, and BT=0 today
05h         TCLP=1, LONG=0, and BT=1 today
06h         TCLP=1, LONG=1, and BT=0 today
07h         TCLP=1, LONG=1, and BT=1 today
08h-1Fh     Reserved

Of course, if any of the TCLP, LONG, and BT bit
combinations are illegal today, then they would be
Reserved too.



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