Re: SAS scsibus target numbering

[Brett Lymn <brett.lymn%baesystems.com@localhost>]

On Fri, Jul 27, 2012 at 09:49:38AM +1000, Simon Burge wrote:
> > 
> > ISTR SPARC machines used an initiator address 6 for hysterical reasons.  I 
> > forget why.
> 
> Likewise for some early models of DECstation (2100 and 3100?).  I never
> understood why.
> 

Priorities.  When negotiating for the bus the highest numbered device
wins if there is an arbitration clash... iirc ids greater than 7 have a
priority lower than id 0, I presume for compat reasons.  So for a scsi
ID 0 - 7 the highest wins, it makes sense that the controller is a high
number (as Mouse said it is normally 7 on old sun hardware) so that it
can grab the bus when it wants to talk.

-- 
Brett Lymn
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