Seagate ST373405LC Starts at 20MB

W

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Mar 17, 2012, 10:36:17 PM3/17/12

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I have multiple Seagate ST373405LC drives attached to an Adaptec SCSI host
adapter. One of these drives only starts at 20 MB per second, whereas all
of the other drives announce to the host adapter at 40 MB/sec. I don't
see a jumper option to slow down the drive. Why would one of the drives
start at a slower maximum throughput?

--
W

daytripper

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Mar 18, 2012, 5:12:53 PM3/18/12

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Sounds like it's running single ended mode. If you're using an adapter from a
cable to the drive, it might not be a differential adapter. Try swapping it
with one from a drive that's running at 40MB/sec and see if the problem moves
with the adapter...

Cheers!

/daytripper

W

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Mar 18, 2012, 9:41:19 PM3/18/12

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"daytripper" <day_t...@REMOVEyahoo.com> wrote in message
news:tqjcm75t0hr13bnkt...@4ax.com...

Strangely, the drives are in a Compaq hotswap case. Slots 1 to 3 start at
40MB and all slots to the right start at 20MB.

--
W

Michael Baeuerle

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Mar 19, 2012, 4:59:15 AM3/19/12

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W wrote:
> daytripper wrote:

> > W wrote:
> > >
> > > I have multiple Seagate ST373405LC drives attached to an Adaptec SCSI
> > > host adapter.
> > > One of these drives only starts at 20 MB per second, whereas all
> > > of the other drives announce to the host adapter at 40 MB/sec.

The drives are "Cheetah 73LP" for which the datasheet specify a
160MByte/s Interface (Fast80 wide). Therefore the transfer mode seems to
be limited by your bus or hostadapter in both cases.

> > > I don't
> > > see a jumper option to slow down the drive. Why would one of the
> > > drives start at a slower maximum throughput?
> >
> > Sounds like it's running single ended mode.

Yes, maybe the Fast20 transfer mode in narrow and wide configurations.

> > If you're using an adapter
> > from a cable to the drive, it might not be a differential adapter. Try
> > swapping it with one from a drive that's running at 40MB/sec and see if
> > the problem moves with the adapter...
>
> Strangely, the drives are in a Compaq hotswap case. Slots 1 to 3 start at
> 40MB and all slots to the right start at 20MB.

You only wrote Adaptec, what model of hostadapter do you use? Does it
support LVD at all?

Micha

Robert Heller

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Mar 19, 2012, 8:03:49 AM3/19/12

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Is this an old 'Dec' style hotswap case? If so, the carriers come in
several 'flavors' (different vintages for different sorts of drives).
Are you sure the all of the carriers are the same?

I'd also inspect the connectors for broken pins and the backplane for
cracked solder traces or broken solder joints. What happens if you swap
the disks, either different slots or different carriers? Does the
problem follow the carier or slot?

>

--
Robert Heller -- 978-544-6933 / hel...@deepsoft.com
Deepwoods Software -- http://www.deepsoft.com/
() ascii ribbon campaign -- against html e-mail
/\ www.asciiribbon.org -- against proprietary attachments

W

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Mar 19, 2012, 2:09:48 PM3/19/12

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"Robert Heller" <hel...@deepsoft.com> wrote in message
news:3uKdnXNNE-s4vfrS...@posted.localnet...

Yes I swap the same drive and carrier between different slots, and the
problem follows the slot not the tray.

--
W

Robert Heller

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Mar 19, 2012, 5:54:13 PM3/19/12

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OK, carefully inspect the SCSI backplane. There is probably something
wrong there (circuit trace problem or something).

T. Keating

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Apr 4, 2012, 11:22:25 AM4/4/12

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On Sat, 17 Mar 2012 19:36:17 -0700, "W" <persis...@spamarrest.com>
wrote:

>I have multiple Seagate ST373405LC drives attached to an Adaptec SCSI host
>adapter. One of these drives only starts at 20 MB per second, whereas all

Use the keyboard during powerup/bios post seq to jump into adaptec
bios config.. The adaptec bios allows you to set max data rates per
device id, those settings will be carried over into the OS drivers.