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Date:      Mon, 01 Apr 96 09:46:25 PST
From:      "Brett Glass" <Brett_Glass@ccgate.infoworld.com>
To:        Michael Smith <msmith@atrad.adelaide.edu.au>
Cc:        hdalog@zipnet.net, davidg@Root.COM, hardware@FreeBSD.ORG, bugs@FreeBSD.ORG
Subject:   Re: Cannot boot after install
Message-ID:  <9603018283.AA828378286@ccgate.infoworld.com>

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> Note that there are some interesting comments in the ATA spec I was
> referring to regarding power-saving modes.  Basically, the "lowest" a
> drive is allowed to go without an explicit command should still respond,
> as per normal, to commands, however response may be delayed by up to 30
> seconds.  If your drive is responding with an error condition (indicating
> that it's gone into 'sleep' mode), it is violating the spec.

In that case, the drive is absolutely within spec. It comes up within 30
seconds.  However, FreeBSD literally locks up until it sees a response fron
the drive. This is a problem with FreeBSD. It should not busy-wait in
the kernel, forsaking all other tasks, until it gets a response. This is,
after all, a multitasking OS! ;-)

The kernel hack I did (turning off the power-saving mode) is appropriate
for desktop machines; in fact, for them, it's a good idea. But it's NOT
appropriate for laptops and other low-power applications. The kernel needs
to be fixed so that the drive *can* spin down without locking up the entire
machine.

--Brett




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