2002-09-22 21:55:27

by Alex Davis

[permalink] [raw]
Subject: scsi error.

While booting my system I got the following error while my
IDE drive was being fsck'd:

Sep 22 17:48:52 test kernel: scsi0: PCI error Interrupt at seqaddr = 0x8
Sep 22 17:48:52 test kernel: scsi0: Data Parity Error Detected during address or write data phase

None of my SCSI drives had been mounted.

I'm running 2.4.19ac4. My hardware: Adaptec 29160 with 3 Maxtor Atlas III drives
(2 internal and one external).

The error did not repeat, and I seem to be able to access my SCSI drives with no problem.
Is this error anything to worry about?

__________________________________________________
Do You Yahoo!?
Yahoo! Finance - Get real-time stock quotes
http://finance.yahoo.com


2002-09-23 14:30:11

by Cress, Andrew R

[permalink] [raw]
Subject: RE: scsi error.

Alex,

There is a linux-scsi list that would be more appropriate for your question.
You apparently have a Data Parity Error on your SCSI bus. Probably your
external SCSI drive has a cable or terminator problem. You can confirm this
by disconnecting the external SCSI cable to see if the other drives come up
ok.
You may be missing some termination, either via an external terminator or by
turning on the drive's TERMPWR jumper on the external drive (depending on
the type of disk cabinet you have). Or, the external SCSI cable may be
faulty (usually bent pins).

Andy Cress

-----Original Message-----
From: Alex Davis [mailto:[email protected]]
Sent: Sunday, September 22, 2002 6:01 PM
To: linux-kern[email protected]
Subject: scsi error.

While booting my system I got the following error while my
IDE drive was being fsck'd:

Sep 22 17:48:52 test kernel: scsi0: PCI error Interrupt at seqaddr = 0x8
Sep 22 17:48:52 test kernel: scsi0: Data Parity Error Detected during
address or write data phase

None of my SCSI drives had been mounted.

I'm running 2.4.19ac4. My hardware: Adaptec 29160 with 3 Maxtor Atlas III
drives
(2 internal and one external).

The error did not repeat, and I seem to be able to access my SCSI drives
with no problem.
Is this error anything to worry about?

__________________________________________________
Do You Yahoo!?
Yahoo! Finance - Get real-time stock quotes
http://finance.yahoo.com

2002-09-24 13:03:11

by jbradford

[permalink] [raw]
Subject: Re: scsi error.

> You apparently have a Data Parity Error on your SCSI bus. Probably your
> external SCSI drive has a cable or terminator problem. You can confirm this
> by disconnecting the external SCSI cable to see if the other drives come up
> ok.
> You may be missing some termination, either via an external terminator or by
> turning on the drive's TERMPWR jumper on the external drive (depending on
> the type of disk cabinet you have). Or, the external SCSI cable may be
> faulty (usually bent pins).

Also, it could be that you are using a cable designed for a Mac - those cables often don't have all of the GND lines individually connected, and can cause seemingly random problems.

John

2002-09-24 15:30:42

by Alex Davis

[permalink] [raw]
Subject: Re: scsi error.

Problem solved. I didn't enable term power on the last drive in my SCSI chain.
Errors gone now. Thanks.


-Alex

--- [email protected] wrote:
> > You apparently have a Data Parity Error on your SCSI bus. Probably your
> > external SCSI drive has a cable or terminator problem. You can confirm this
> > by disconnecting the external SCSI cable to see if the other drives come up
> > ok.
> > You may be missing some termination, either via an external terminator or by
> > turning on the drive's TERMPWR jumper on the external drive (depending on
> > the type of disk cabinet you have). Or, the external SCSI cable may be
> > faulty (usually bent pins).
>
> Also, it could be that you are using a cable designed for a Mac - those cables often don't have
> all of the GND lines individually connected, and can cause seemingly random problems.
>
> John

__________________________________________________
Do you Yahoo!?
New DSL Internet Access from SBC & Yahoo!
http://sbc.yahoo.com

2002-09-24 15:56:21

by jbradford

[permalink] [raw]
Subject: Re: scsi error.

> > > You apparently have a Data Parity Error on your SCSI bus. Probably your
> > > external SCSI drive has a cable or terminator problem. You can confirm this
> > > by disconnecting the external SCSI cable to see if the other drives come up
> > > ok.

> > > You may be missing some termination, either via an external terminator or by
> > > turning on the drive's TERMPWR jumper on the external drive (depending on
> > > the type of disk cabinet you have). Or, the external SCSI cable may be
> > > faulty (usually bent pins).

> > Also, it could be that you are using a cable designed for a Mac - those cables often don't have
> > all of the GND lines individually connected, and can cause seemingly random problems.

> Problem solved. I didn't enable term power on the last drive in my SCSI chain.
> Errors gone now. Thanks.

Hmmm, that is a bit strange - you don't specifically need to enable term power on the last device on the chain - both ends have to be terminated, but any device can supply the termination power to the bus, and only one device needs to do that. Usually all devices are configured to do that, but it is usually considered to be the host adaptor that can be relied on to provide term power. The exceptions are usually parallel port SCSI adaptors, which cannot supply enough power.

In any case, there is no harm in all devices supplying term power, as they, (should), be protected with diodes to prevent wrong voltages reaching the devices.

Having said all that, if it's fixed the problem, great. I would double check the following, though:

* Term power enabled on at least one device, (already done)
* Both ends terminated with ACTIVE terminators, (never EVER use passive terminators, they do NOT work reliably, they might work, but it really is worth paying the extra for active terminators. Even the original SCSI spec suggested active terminators. I think that passive terminators were a dinosaur from the days of SASI, (Shugart Associates System Interface), which is way, way, WAY back in time :-) ).
* Cable length does not exceed the recommended maximum, (1.5 metres for Ultra-SCSI).
* The cables are good quality
* Parity is enabled.

John.

2002-09-24 17:41:26

by Alex Davis

[permalink] [raw]
Subject: Re: scsi error.

Ahh, I forgot to mention that none of my drives were supplying term power.

I believe I'm using a high quality cable: the wires between the connectors
are braided; it only about two feet long.

I have an LVD/SE terminator on the last connector.

As for parity, the drive doesn't have a parity jumper on it. I'll assume that
parity is enabled.

BTW, it is really difficult to find the small jumpers these newer drives need.
Especially since a lot of online resellers sell the drive only, with no accessories.

Thanks for your input.

-Alex

--- [email protected] wrote:
> Hmmm, that is a bit strange - you don't specifically need to enable term power on the last
> device on the chain - both ends have to be terminated, but any device can supply the termination
> power to the bus, and only one device needs to do that>
> John.


__________________________________________________
Do you Yahoo!?
New DSL Internet Access from SBC & Yahoo!
http://sbc.yahoo.com