SCAM Questions
John Lohmeyer
jlohmeye at ncr-mpd.FtCollinsCO.NCR.COM
Wed May 4 08:41:30 PDT 1994
> Larry Lamers wrote:
> >
> > 6) Can we get rid of the abhorent terminology and used
> > SCSI terminology.
> >
> > A SCAM master is really a SCAM initiator. A SCAM slave is
> > really a SCAM target.
then Jon Buckingham wrote:
> My understanding of these definitions is this...
>
> Master : Controls iterations, i.e. transfers synchronisation
> codes, function codes, action codes.
>
> Slave : participates in isolation stages in order to be
> assigned an action code (typically an ID).
> There may be several slaves participating at once.
>
> Initiator : performs SCAM arbitration and selection (initiates SCAM
> protocol).
> i.e. for level 1, is always the SCAM master.
> for level 2, may be a master or slave.
>
> So the SCSI concept of initator and target doesn't really fit SCAM.
>
> Is this a correct interpretation?
>
> Jon Buckingham
I agree with Jon. Master and Slave are separate concepts from Initiator
and Target. However, I do expect that 99.44% of all Masters will also be
Initiators and 99.44% of all Slaves will be Targets. Changing this terminology
would create more problems than it would solve.
Another point that bothers me in this thread is of mixing level 1 and
level 2 SCAM masters on the same bus. While I agree with others that this
is desirable, I feel that the best (perhaps only) way to make this work
is to require level 1 masters to recognize dominent master contention. It
is not necessary for level 1 masters to initiate the dominient master
contention protocol, but they must react correctly if a level 2 master
initiates dominent master contention. Perhaps, we should call such
SCAM masters level 1.5. They are mostly level 1, but they can be mixed
with level 2 SCAM masters.
John
--
John Lohmeyer E-Mail: John.Lohmeyer at FtCollinsCO.NCR.COM
NCR Microelectronics Voice: 719-573-3362
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