Skip site navigation (1)Skip section navigation (2)
Date:      Fri, 27 Dec 1996 17:02:46 +0100 (MET)
From:      J Wunsch <j@uriah.heep.sax.de>
To:        freebsd-scsi@FreeBSD.org (FreeBSD SCSI list)
Cc:        msmith@atrad.adelaide.edu.au (Michael Smith)
Subject:   Re: cvs commit:  src/sys/scsi cd.c
Message-ID:  <199612271602.RAA13776@uriah.heep.sax.de>
In-Reply-To: <199612271158.WAA27787@genesis.atrad.adelaide.edu.au> from Michael Smith at "Dec 27, 96 10:28:28 pm"

next in thread | previous in thread | raw e-mail | index | archive | help
As Michael Smith wrote:

> The "unit is not spinning" status should probably be an error/status
> return to the generic SCSI layer in the "ideal world".

Why?  No.  For example, i've added extra code to the od driver to
(optionally) take the drive down if it's idle.  I know that other
people have also been requesting this for fixed disks, e.g. in cases
where they use it as an archive disk which is only rarely used and
generates enough noise so you don't wanna have it running all the
time.  Actually, the guy requesting this even thought of a timeout-
controlled spindown, while my code only uses device open/close events.

> > Why do you want to have the disks spun up at probe time?  IMHO,
> 
> Because there are no other demands on the system at that point in time.

There are no other activities on that particular drive at device open
time either, provided you catch multiple open's with a driver-internal
flag.  Things are more complicated for a timeout-controlled spindown,
but even then, you can still arrange for that target not seeing
multiple commands.

-- 
cheers, J"org

joerg_wunsch@uriah.heep.sax.de -- http://www.sax.de/~joerg/ -- NIC: JW11-RIPE
Never trust an operating system you don't have sources for. ;-)



Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?199612271602.RAA13776>