Re: kupdate & laptop's [patch for integration of mobile-update]

Peter Englmaier (ppe@pa.uky.edu)
Sat, 14 Aug 1999 20:41:51 -0400 (EDT)


> There must be something wrong in your setup. I don't experience these
> problems. If a simple <ls> triggers a spin-up, then check to make sure
> you're mounting with the "noatime" flag. By default, a simple read of
> a file/directory will cause the inode access time to be updated, which
> in turn requires the disc to be written to.

OK, 'noatime' does the trick. Many Thanks. It doesn't help, of course,
if I edit/compile/run the same program over and over again. Even when
I turn of 'auto-save' in emacs, it still does something from time to
time (while typing).

> Configuration, configuration, configuration. The problem is that a lot
> of stuff in user space expects to write from time to time. Tracking
> down those places can take a while, but I assure you that's where the
> problem lies.
Sure. But many people won't be able to do that, and 'mobile-update'
makes it much easier IMHO. In that case, you would only care for fsync's
(basically syslog). You can have 'noatime' if you need it for
some reason, and you won't care about frequent but tiny cron jobs like
'rmmod -a' at all. Actually, with my patch it's pretty much like working
on a ramdisk.

> BTW: I don't know what kind of disc drive you have, but mine takes
> very little extra power when spun up. My Dell Inspiron takes ~800 mA
> when idle (but screen lit) and ~1.1 A when busy. Spinning down the
> disc saves 10 -> 20 mA at most. Really, it's bugger-all.
I have an IBM (DADA 26480) drive, which claims to use: 1W in 'active
idle' and only 0.1 W in 'sleep' mode. My laptop needs on average 14W.
I I figured out that this would give only 6% more battery live (10
minutes), or 12% when compared to 'performance idle' mode (20
minutes). Not a big deal and with bigger screens even less, I agree.

Cheers, Peter

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