I don't believe any of this crud is necessary. My laptop uses 2.2.11
with kupdate, I never disable it, and the disk spins down and stays
spun down. I am convinced that any instance where a disk will not
stay spun down can be tracked to userland bugs or userland
misconfiguration.
The commonly used version of atd will wake up the disk because it
checks for new jobs by rereading the queue directory every so often.
I had to patch it to stat the directory first. Other persistent
daemons may have the same problem - sendmail, lpd, etc. It's not
necessarily safe to stat files, but that information seems to be
cached a lot longer than file/directory data. fstat is always safe,
and so is stat(".").
In the misconfiguration category, you can't have cron jobs that
trigger every few minutes. Nor can you use qmail-spawn or whatever
it's called. Anything that has to happen periodically has to be
handled by a persistent daemon which does not exec. The big problem
here is "rmmod -a" in a cron job. I sent a patch implementing a
trivial daemon to the modutils people, but they never responded.
Another common misconfiguration is if you have syslogd set up to write
--MARK-- into the logs every 20 minutes.
zw
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