Date: Thu, 23 May 1996 22:12:32 +0100 (GMT-1) From: af@biomath.jussieu.fr To: freebsd-scsi@freebsd.org Subject: How to send "start unit" to disk during boot? Message-ID: <199605232112.WAA03275@garfield.biomath.jussieu.fr>
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Hi FreeBSDers,
I have been given a DEC RZ24 (200Mb) SCSI disk which I have
successfully connected to my PC (133Mhz Pentium, Intel Endeavour m/b,
AHA2940 controller, IDE boot disk). This disk, like some other DEC
disks, does *not* spin up when powered up. Other DEC disks have
jumpers to change this, the RZ24 doesn't seem to have them.
When I boot DOS or enable the AHA2940's BIOS, I can hear the drive
spin up and see the driver wait for it to become ready. If I don't
enable the AHA2940's BIOS and I boot FreeBSD (2.1-RELEASE), the disk
is not spun up and the mount fails (note that the mount attempt
actually causes it to start spinning, but the FreeBSD driver obviously
does not wait at that time, the SCSI_DELAY wait occurs *before* the
mount attempt). If I soft reboot (CTRL-ALT-DEL) the machine at this
point, the next boot completes OK.
>From the FAQ, I can guess that the SCSI inquiry FreeBSD sends before
waiting SCSI_DELAY does *not* cause the disk to start, and then the
subsequent mount attempt fails. I don't want to enable the AHA2940 BIOS
because I want to save high memory for DOS usage (this is a multi-OS
machine) and I'd really love to have this machine boot unattended.
How can I make FreeBSD issue a "start unit" command to the disk
*before* it waits for SCSI devices to settle ? From my reading of
./sys/scsi/sd.c and cd.c, it seems to me that such a thing is done for
CDROM units, but not for disks.
Another possibility I imagined would be to add a scsi(8) command (and
a sleep(1)) at the very beginning of /etc/rc to send a "start unit" to
the disk. But:
1) this really is an ugly hack (hardcoded device names in /etc/rc)
2) I have not even managed to use scsi(8) to do that, all my attempts
(like "scsi -f /dev/rsd0c -c "1b 0 0 0 1 0") have at best produced i/o
errors. I even have locked up the machine tight sometimes (SCSI
bus hung)
Would someone please enlighten me ?
Thanks in advance,
_Alain_
--
Alain FAUCONNET Ingenieur systeme - System Manager AP-HP/SIM
Public Health 91 bld de l'Hopital 75013 PARIS FRANCE
Medical Computing Research Labs Mail: af@biomath.jussieu.fr
Tel: (+33) 1-40-77-96-19 Fax: (+33) 1-45-86-80-68
I've RTFMed. It says: "Refer to your system administrator"
But... I *am* the system administrator :-]
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