Date: Mon, 15 Mar 1999 10:44:01 -0800 (PST) From: Matthew Dillon <dillon@apollo.backplane.com> To: Steve Passe <smp@csn.net> Cc: hackers@FreeBSD.ORG Subject: Re: power-off without halt Message-ID: <199903151844.KAA01410@apollo.backplane.com> References: <199903151655.JAA28147@Ilsa.StevesCafe.com>
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:Hi,
:
: We are looking at using FreeBSD as an "embedded OS" inside a line
:of instruments we are building. I think I have a handle on all the
:issues except how to cleanly handle shutdown where there is no
:console, and thus no way to send a 'halt' command. The requirement
:is that the user can merely turn off the power, nothing more required.
:
: I can modify the disk setup, kernel/util code as needed, I just need some
:idea for a workable solution. Has anyone delt with this problem before?
:
:--
:Steve Passe | powered by
:smp@csn.net | Symmetric MultiProcessor FreeBSD
Well, physically speaking you can't power off a machine that may
be writing to its disk. If it is in the middle of a write, you
*will* lose sectors to hard errors.
So, typically, the best way to deal with this sort of situation is
to mount the disk read-only and never write to it. Or to not have a
disk at all. Or to use a pcmcia type flash disk.
-Matt
Matthew Dillon
<dillon@backplane.com>
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