On 10/09/2017 08:52 AM, Jules Richardson via cctalk wrote:
My understanding there is that true SASI supports just a
single target, and so there's no selection phase like
there is with SCSI
No, not true. Each of the 8 data lines selected one target,
so you could have 8 targets on one controller.
(and SCSI provides an extra signal on the connector uses
during selection, which simply isn't there with SASI).
However, there seemed to be some significant overlap and
blurring of lines between SCSI and SASI, such that some
early devices calling themselves SCSI aren't quite - and
it's possible that some hardware which talks about SASI
actually behaves more like SCSI.
Yes, I'm sure this was true, as vendors moved their code
over to comply with the new standard.
I don't think SASI had any parity support, either - but I
think that in a lot of cases early HBA's relied on parity
checking in software, which meant that it could simply be
ignored.
I looked up my SASI interface, and I didn't see any parity
circuit there.
Jon
