Re: faster boots?

[Rogier Wolff]

Itai Nahshon wrote:
> On Saturday 06 April 2002 02:07 am, Benjamin LaHaise wrote:
> > On Sat, Apr 06, 2002 at 02:02:36AM +0300, Itai Nahshon wrote:
> > > A required feature IMHO: there should _never_ be dirty blocks
> > > for disks that are not spinning.
> >
> > Never make assertions like that: on my laptop, I want *lots* of
> > dirty blocks held in memory while the disk isn't spinning.  Keeping
> > RAM powered is much less costly than spinning the disk up.
> >
> > 		-ben
> 
> I figure that if there are dirty blocks that belong to files that you
> want to keep, they must be flushed at some time, probably on the
> next sync(). On "normal" systems that's likely to happen in less
> than a minute.
> 
> I admit that what I had in mind was medium-large systems with
> multiple disks where some of the disks have very little activity
> or small systems where there is really zero disk activity for
> a long time.
> 
> I'm curios, how much work can you accomplish on your laptop
> without any disk access (but you still need to save files - keeping
> them in buffers until it's time to actually write them).

On a laptop you can decide to "trust" the drive to spin up, just
because the benefits outweigh the drawbacks.

The benefit may be: Battery life becomes 8 hours instead of 4. That
might mean that you get 4 hours of extra work done while travelling at
$100 per hour.... 

Just editing source-code using VI, or reading docs can leave your 
disk completely idle for hours at a time. 

Debugging an app, compiling testing, recompiling can leave your disk
idle provided you accept dirty blocks in the buffer cache...

			Roger. 

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