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From: Stefan Monnier <monnier@iro.umontreal.ca>
Newsgroups: comp.os.linux.development.system,comp.unix.programmer
Subject: Re: Getting time of last reboot on Linux
Message-ID: <jwv4nw5ezc6.fsf-monnier+comp.unix.programmer@gnu.org>
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NNTP-Posting-Date: Mon, 09 Jan 2012 14:18:38 UTC
Date: Mon, 09 Jan 2012 09:18:28 -0500
Xref: x330-a1.tempe.blueboxinc.net comp.os.linux.development.system:378 comp.unix.programmer:1964

> I would expect that it would be near 100% on systems where there
> is no real-time-clock kept alive when the system is powered off,
> and the system has to resort to a mod time on the root superblock
> from shutdown.  Scheduled shutdowns (systems not expected to run
> anywhere close to 24/7 for power-saving, security, noise, or other
> reasons) or shutdowns for hardware reconfiguration are likely to
> take more than 10 minutes.  I'll assume that the system is robust
> enough not to have a lot of panic/immediate reboot cycles.

FWIW, it *is* 100% on many/most home routers I know, since they don't
have any RTC, and they don't try to do anything fancy with the root
superblock (they try to touch the flash as rarely as possible) nor do
they even shutdown usually (they're just power cycled instead).


        Stefan