SUMMARY: Controlling disk spin-up on boot .......

From: Thomas Leitner <tom_at_finwds01.tu-graz.ac.at>
Date: Wed, 29 Jul 1998 18:47:42 +0200 (MET DST)

Hi,

Briefly: Yes it works. I've just added the new disk, set the
"enable motor start" jumper on all of my disks and Digital Unix spins
up the disks when it starts to boot.

Thanks to: "Dr. Tom Blinn, 603-884-0646" <tpb_at_zk3.dec.com>
            Alan Rollow - Dr. File System's Home for Wayward Inodes.
                                         <alan_at_nabeth.cxo.dec.com>
           "Kristin (Kris) Larsen" <klarsen_at_enterprise.afit.af.mil>

for their replies which I'm attaching below followed by my original
posting.

Thanks // Tom

---------------------------- answers --------------------------
From: "Dr. Tom Blinn, 603-884-0646" <tpb_at_zk3.dec.com>

DIGITAL UNIX won't send the spin-up to the drive until you actually try to
touch the drive in some way. For instance, if you attempt to mount a file
system from the drive, and the drive isn't active, DIGITAL UNIX will send
the appropriate SCSI commands to spin up the drive, determine its type, and
so on. Of course, normally the SCSI busses are probed during initialization
and that constitutes the kernel trying to touch the drive, so it will spin
up at that point if the kernel can communicate with it.

In other words, what you're proposing should work just fine.

Tom
---------------------------------------------------------------
From: Alan Rollow - Dr. File System's Home for Wayward Inodes.
    <alan_at_nabeth.cxo.dec.com>

As far as I know, the driver does send a Start command, when it
first notices a device.

---------------------------------------------------------------
From: Alan Rollow - Dr. File System's Home for Wayward Inodes.
    <alan_at_nabeth.cxo.dec.com>

He said the same thing I did. I don't see the problem. When a
system boots, it queries each device it finds on the bus. As
a consequence of that it sends the Start (Start-unit) command.
For devices that appear after boot, the first real access will
cause the command to be sent. Using scu(8) to merely scan the
bus, probably does no more than send an Inquiry command, which
doesn't.

---------------------------------------------------------------
From: "Kristin (Kris) Larsen" <klarsen_at_enterprise.afit.af.mil>

Tom -

>From my past experience, the ST designates a Seagate drive. To
use any disk spin-up it must be enabled on the drive. Go to
Seagate's website (www.seagate.com) and you can print a copy
of the disk booklet and even more complete tech data on it.

Kris Larsen

---------------------- original posting -----------------------

Hi,

In about three hours time, I'll be installing a new ST39173W 9.1GB wide
disk in our Alpha running Digital Unix 4.0D (brand new patch kit #2
applied), using an IntraServer ITI3140 controller.

What I have in mind, is to set the "enable motor start" jumper on the
drive in order to delay the disk spin-up until the machine is booting. As
this is already the third drive in the box, this would cause the startup
load on the power-supply to be not so high.

So my question: Does Digital Unix send a "spin-up" SCSI command to every
disk device while booting? If no how can this be turned on?

Thanks a lot // Tom

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Received on Wed Jul 29 1998 - 16:48:49 NZST

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