Date: Mon, 12 Apr 1999 10:32:25 -0700 From: Darryl Okahata <darrylo@sr.hp.com> To: Steve Howe <groggy@iname.com> Cc: freebsd-scsi@FreeBSD.ORG, freebsd-questions <questions@FreeBSD.ORG> Subject: Re: board not responding Message-ID: <199904121732.KAA09157@mina.sr.hp.com> In-Reply-To: Your message of "Fri, 09 Apr 1999 23:20:48 -0800." <Pine.BSF.3.96.990409224603.1844A-100000@en26.l1.net>
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Steve Howe <groggy@iname.com> wrote:
> > > ahc0 <Adaptec 2940 Ultra SCSI adapter> rev 1 int a irq 10 on pci:0:10:0
> > > ahc0: aic7800 Wide Channel, SCSI Id=7, 16 SCBs
> > > ahc0 waiting for scsi devices to settle
> > > (ahc0:0:0): "IBM DDRS-34560D DC1B" type 0 fixed SCSI 2
> > > sd0(ahc0:0:0): Direct-Access 4357MB (8925000 512 byte sectors)
> > > ahc0: board is not responding
>
> > > (term) (auto) (term)
> > > IBM DDRS-34560 HD <-> 2940UW <-> Toshiba 6401B CD <-> HP 4020 CD/RW
> > > 68 pin 50 pin 50 pin
>
> i hear what you are saying, but don't know what it means.
> usually when i hear "single-ended", i think "as opposed to differential".
>
> the IBM spec sheets for the drive state:
> "Enable SCSI terminator SE 50/68 pin"
Sorry, I was a bit unclear in my last posting. Here's what I'm
trying to say:
* The IBM Ultrastar 9ES (which is what you and I have) comes in both
single-ended and LVD (Low-Voltage Differential) versions.
[ Yes, the IBM drives do come in 68-pin LVD versions. ]
* LVD drives can often be used with single-ended controllers.
* The "IBM DDRS-34560D DC1B" is an LVD drive. On the drive, look for
"LVD" on the little white label.
* LVD drives DO NOT HAVE PROVISION FOR ON-DRIVE TERMINATION. LVD drives
cannot be used to terminate the SCSI bus. You need an external
terminator.
* In the case of the IBM DDRS-34560D, the jumper that controls
"termination" does not control termination (LVD drives don't have
any provision for on-drive termination). Instead, this jumper
controls whether or not the drive runs in LVD or plain old
single-ended mode.
* IBM really does make LVD drives in a 68-pin configuration. See the
first page of this PDF file:
http://www.storage.ibm.com/techsup/hddtech/ddrs/ddrs.pdf
Note the line that says, "SCSI-3 FAST-40 (68 & 80-pin (L)ow (V)oltage
(D)ifferential)".
* If you still don't believe you have an LVD drive, check out these
DejaNews postings:
http://www.dejanews.com/[ST_rn=ps]/getdoc.xp?AN=441444978
http://www.dejanews.com/[ST_rn=ps]/getdoc.xp?AN=436967059
http://www.dejanews.com/[ST_rn=ps]/getdoc.xp?AN=436728277
* For more info, Adaptec's web site has some good info on LVD:
http://www.adaptec.com/products/solutions/ultra2.html
> but when i add the Toshiba, with either the IBM or the HP
> in addition, the SCSI bus dies as shown above.
... which is consistent with termination problems (among other
possible things).
--
Darryl Okahata
darrylo@sr.hp.com
DISCLAIMER: this message is the author's personal opinion and does not
constitute the support, opinion, or policy of Hewlett-Packard, or of the
little green men that have been following him all day.
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