SCSI-2 Parity Errors
James.Kahn at Eng.Sun.COM
Fri Mar 17 09:30:24 PST 1995
I have seen occassional parity errors from worn cabling
(damaged that is). I have see *HEAVY* parity errors with
long cables and SCSI chip problems. Otherwise, it's
fiarly rare for me.
> From @ncrwic.WichitaKS.NCR.COM:asami at dt.wdc.com Thu Mar 16 19:16:21 1995
> From: asami at dt.wdc.com (Tak Asami)
> To: scsi at wichitaks.hmpd.com
> Subject: Re: SCSI-2 Parity Errors
> I usually don't respond to discussion like this, but this is too exciting
> to pass up.... Here's my two cents.
> Have anyone ever seen in this life an "occasional" occurance of SCSI parity
> error? In my limited experience, it either never happens or happens ALL THE
> TIME. In other words, all parity errors I've seen are hard errors.
> Where do parity errors come from? Intermittent cable/connector connection,
> cold solder joints on your Heathkit SCSI drive, disintegrating PC board trace,
> a dead device on the bus (OJ did it!).
> This is definitely a different animal from bit error rate on magnetic record-
> ing read-write!
> My immediate reaction to SCSI parity error is that the bus must be suffering
> a catastrophic failure. And any transfer across the bus is deemed unreliable.
> Forget the message, forget the sense data. You can't use it.
> Forget the tricky error recovery.
> The best policy in my mind is like Jim Mcgrath says, abort everything and
> start over. It doesn't take that long. And for a "working" system, you'll
> never have to do it, anyway.
> Tak Asami
> _|_|_| asami at dt.wdc.com
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