Date: Wed, 29 Sep 1999 07:52:44 -0700 From: C Polisher <cpolish@ns.net> To: gregory.hosler@eno.ericsson.se Cc: aic7xxx@FreeBSD.ORG Subject: Re: fast drives. Message-ID: <37F227BC.E5674869@ns.net> References: <XFMail.990929141913.gregory.hosler@eno.ericsson.se>
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Gregory Hosler wrote:
> does anyone have experience w/ a large (9 Gb or larger) fast/wide drive,
> running on a aic7xxx (obviously) at full speed (40 Mb/s), with tagged
> queueing enabled.
>
> The reason I ask is that I have a new IBM drive, I had to disable tagged
> queueing, and further slow it down to 34 mb to eliminate any spurious errors
> (that are otherwise described as "termination/cabling problems").
I've had no problems with the IBM 9.1GB SCSI,
hope some of this info helps. Sounds very much like
a cabling / termination problem. Are you using an
active terminator on your SCSI chain?
I'm appending verbatim a message I snagged a couple of years
back from the Redhat list, some of the advise might help?
My setup:------------------------------
distro: SuSE 6.2
kernel: 2.2.10 (SMP)
motherboard: ASUS P2B-DS
drive: IBM DDRS-39130D
SCSI Adapter: Adaptec AIC-7890/1 Ultra2 SCSI host adapter
Ultra-2 LVD/SE Wide Controller
Adaptec SCSI BIOS: Enabled
Extended Translation: Enabled
Disconnect Enable Flags: 0x000f
Ultra Enable Flags: 0x0000
Tag Queue Enable Flags: 0x000e
Ordered Queue Tag Flags: 0x000e
Default Tag Queue Depth: 8
Tagged Queue By Device array for aic7xxx host instance 0:
{0,0,0,0}
Actual queue depth per device for aic7xxx host instance 0:
{1,8,8,8}
scsi0:0:2:0
Device using Wide/Sync transfers at 40.0 MByte/sec, offset 15
Transinfo settings: current(12/15/1/0),
goal(10/127/1/0),
user(10/127/1/0)
Host: scsi0
Channel: 00
Id: 02
Lun: 00
Vendor: IBM
Model: DDRS-39130D
Rev: DC1B
----------------------------------------
Re: scsi question ("Robert G. 'Doc' Savage" , Wed 19:25)
To:
redhat-list@redhat.com
Jason,
If it works at 10 MHz but not at 20 MHz, this is almost certainly an
electrical transmission problem at a very low (i.e. "copper") level.
Unless you stepped on and crushed your Buslogic, or accidentally dropped
your Fujitsu on a concrete garage floor, they're both fine.
I suggest the following troubleshooting sequence:
(1) Starting at the host adapter, follow your SCSI cable from device to
device. Look for sections under tension that could pull apart a drive
connection. There should be sufficient slack between each device.
(2) Check the termination settings on every drive in the chain. The last
physical device on the cable must be terminated, and all others must not be.
(3) If you have both external and internal drives, your card should
auto-disable its on-board termination. Check your manual to be sure you
haven't inhibited this capability in any way.
(4) Replace the internal cable with a premium grade cable (look for Ultra
recommendation) no longer than 72". I suggest Cables-To-Go as a source.
(5) If your system uses a termination block on the cable instead of
termination resistors on a drive, it should be an active type rather than
passive. If buying a new terminator block, I would opt for Cables-To-Go's
"forced perfect termination" (FPT) active terminator.
--Doc Savage
P.S. You're not fastclocking your PCI bus are you? I don't know how well
the BusLogic would tolerate a 75 MHz or 83 MHz bus clock.
At 16:05 12/9/97 -0500, Jason Philbrook wrote:
>Got a Buslogic 948 (very nice controller) and a Fujitsu 4GB ultra-scsi
>drive.
>
>At 10-megatransfers a sec setting in the buslogic setup, I get zero
>messages in dmesg. At 20-meg a sec, I've been getting a few of these. I'm
>quite confident in the drive - could poor cabling or other conditions
>cause problems at 20meg and not 10meg speeds? Of what importance are
>these messages? What action would be appropriate on my part?
>
>TIA for any suggestions.
>
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