[4446] in linux-scsi channel archive
RE: Trouble with Pioneer CD-Changer
daemon@ATHENA.MIT.EDU (Gerard Roudier)
Sat Jul 25 14:38:30 1998
Date: Sat, 25 Jul 1998 19:40:20 +0200 (MET DST)
From: Gerard Roudier <groudier@club-internet.fr>
To: Ryan Kirkpatrick <rkirkpat@nag.cs.colorado.edu>
cc: Dave Wreski <dave@nic.com>, linux-scsi@vger.rutgers.edu
In-Reply-To: <Pine.LNX.3.95.980725113735.979B-100000@farstar.rkirkpat.net>
On Sat, 25 Jul 1998, Ryan Kirkpatrick wrote:
> On Sat, 25 Jul 1998, Dave Wreski wrote:
>
> > This drive uses a Centronix 50-pin connector, doesn't it? So you are converting
> > a 50-pin device all the way to a 50 (or possibly even 68-pin) connector?
>
> This drive connects from the tape drive through a Centronics 50 to
> MiniDB50 or HD DB50 (what ever you want to call it) converter.
>
> > If so, I'm sure your problems likely stem from that. That, in conjunction with
> > your other CD errors, leads me to believe you've got a serious termination
> > problem. Go over all your devices and make sure cable lengths and termination
> > is properly set.
>
> I know the cabling is perfectly fine. I have a scanner, then a
Each time I have had problems with SCSI, I was sure my cabling was fine
but I was almost sure the cause was in either cabling or terminations.;)
> cdrom drive, then the tape drive, then into the computer. With this setup
> everything works fine without a single error. The scanner terminates the
> bus correctly, and I have never had any problem with any device. I
Best terminations are _active_ terminations. Scanners generally have
passive terminations and often implement SCSI badly and sometimes
wrongly. Unless you are sure it has good firmware, you should use a
separate SCSI controller for it.
> replaced the cdrom drive with the cd changer, just swapped them, no cable
> changes at all, and I began to get endless errors, and devices failing to
> respond. Most of the errors are either "data phase in" parity failures
> (tried setting the cd changer drive with dip switches to both parity and
> no parity, no change), scsi timeouts (have increased the timeout in the
> kernel three fold, no change), and bus resets.
Bad phase, parity errors, timeouts, etc... are the usual symptoms of a
non compliant SCSI BUS.
You should try using your device at a lower data transfer speed, or even
in asynchronous mode.
If they work better, then it is almost sure the SCSI BUS is bad.
On a bad SCSI BUS, some devices may work since they have a better margin
on actively driving REQ/ACK and DATA lines and/or filtering signals but
some other may not work.
But when the SCSI is OK, all devices should work unless some are actually
broken.
AFAIR, you wrote in a previous message that another O/S seemed to be happy
with the device or perhaps another controller.
Did that O/S or the other controller use the same data transfer speed as
the ones that fail with the device?
> > If your still having problems, or sick of pulling your hair out, spend a few
> > bucks on an additional cheap IDE or even PCI controller to drive your external
> > devices.. Works beautifully.
>
> Sorry, I have all of my PCI slots filled up with 2 SCSI
> controllers (one for fast devices, one for normal, external scsi devices),
> a NIC, and a video card. I am trying to get away from IDE. If this cd
I donnot use IDE at all on my systems and never have had problems with
them that was not due to a bad SCSI BUS. Firmware problems may also
mess up a SCSI BUS, but it is rare compared to bad SCSI BUS.
> changer will not work with Linux, just tell me and I will take it back. I
> just bought it becuase it was at a good price and might be nice for
> playing audio CDs. Thanks for the help.
Regards,
Gerard.
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