Date: Wed, 07 Oct 1998 03:15:42 -0500 From: Doug Ledford <dledford@dialnet.net> To: "Karl O. Pinc" <kop@meme.com> Cc: aic7xxx@FreeBSD.ORG Subject: Re: pre15 woes w. both 68pin & 50pin Message-ID: <361B232E.65BDEB79@dialnet.net> References: <XFMail.981006153618.kop@meme.com>
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Karl O. Pinc wrote:
>
> 2.0.35 kernel w. pre-15 patch (& redhat patches)
> Micronics W6LI motherboard w. built in aic7880u & adaptec bios 1.24
> (dual PPro, but running w/o SMP -- which I suspect fails)
> 4 Seagate ST-15230W hard drives (68 pin)
> (and, in the following physical order)
> Yahama 4260t series CDRW (50 pin), internal
> Python Dat tape drive (scsi II), external
> HP scanner detected as a C2520A (w. 1 centronics & 1 ugly 25pin D connector)
> Epson zip drive, external (Iomega licensed knock off w. 25pin D
> connectors & internal termination on)
>
> attempt to access beyond end of device
> 08:01 : rw=0 wait=747850753, limit=164848
> (scsi0:0:0:0) Parity error during Data-In phase.
> As usual, I'd be happy to supply further information. I also welcome
> any suggestions that might get my system working! Is it just a bad idea to try
> to get all these devices on the same bus? I wouldn't mind putting the
> scanner and zip drive on a new cheap scsi card, but would like to keep the
> others.
OK...a few suggestions. Yes, you probably are trying to slide too much
stuff onto one bus. Personally, I like the 2910C cards for something cheap
to separate things up and that also works fine with external stuff. Second,
the errors you note indicate that there may already be bad data written to
the disks as a result of all of this. A SCSI bus will catch single bit
parity errors and pass 2 bit errors without any notice of problem. From
what I see, you may be susceptible to the dual bit error problem. There is
simply too much going wrong on your bus to trust that all errors will get
caught by parity. I would see about getting a custom made internal wide
cable for the drives that only leaves about 3 to 4 inches between each wide
drive, terminate the last wide drive of course, hook the other end to the
controller and terminate the controller. Then, don't hook any narrow
devices to that controller. I would use something like the 2910C for all
narrow devices be they internal or external (this assumes none of the
internal stuff is Ultra, if it is, then you would need something like a
2940AU instead).
--
Doug Ledford <dledford@dialnet.net>
Opinions expressed are my own, but
they should be everybody's.
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