Poor SCSI drive performance FIXED on SMP machine, 2.2.16
Thanks! I have added a terminator to the SCSI bus and also turned on TCQ and now
I can write out 100 MB in 10 seconds (as opposed to several minutes)
Regards, Para-dox ([email protected])
----- Original Message -----
From: "Trevor Hemsley" <[email protected]>
To: "paradox3" <[email protected]>
Sent: Sunday, January 28, 2001 8:56 PM
Subject: Re: Poor SCSI drive performance on SMP machine, 2.2.16
Quoted 5 lines · On Sun, 28 Jan 2001 19:58:04 -0500, paradox3 wrote:
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I've attached the output in the kernel ring buffer as it initializes the scsi drive. I haven't been
able to find IBM's website for DGHS09U to see if it self terminates.
Maybe
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you
can tell.Yeah, I have the PDF manual for that one here too - I used to have one.
It's a Single ended
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(ie not LVD), fast, wide 7200rpm drive with a 68 pin connector. It has a
top speed of about
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14MB/sec. Pretty good drive in its day. It's the 7200rpm drive of the same
generation as my
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DGVS09U - the manual I have is dated October 1997.
From the manual...
Enable Active Termination
Single Ended 50 and 68 pin models are available with on card SCSI Bus
Active Terminators.
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The Active Termination feature can be enabled by installing a jumper
between pins 13 and 14
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of the Front Option Jumper Block or connecting pins 9 and 10 of the
Auxiliary Connector on
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68 SCSI pin models. SCA-2 80 pin has no termination.
If you need more information about the drive, IBM are usually pretty good
at keeping it on
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their web site, http://www.storage.ibm.com should get you more.
I'd guess you need to jumper pins 13+14 of the front jumper block *or*
pins 9+10 of the jumper
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block on the back that lies between the power connector and the 68 pin
cable connector. On
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the back connector pins 1+2 are the ones nearest the power connector. On
the front connector
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pin 1 is the lefthandmost pin when you look at it with the PCB downwards
and the front of the
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drive towards you.
Since this looks like it's the only device you have attached to the
controller then you should also
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look in the BIOS setup (Ctrl-A at boot time) and find the section that
talks about controller
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termination. You can either set this to Automatic which usually works but
sometimes gets it
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wrong or you can set it to Low On/High ON which is correct if you have no
external devices
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and no devices attached to the internal 50 pin connector.
Trevor Hemsley, Brighton, UK.
[email protected]
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