I think this link probably explains what is happening:
http://www.microsoft.com/resources/documentation/windows/xp/all/proddocs/en-us/fsutil_dirty.mspx?mfr=true
Basically there is a "dirty bit" in the file system and if the system goes down unexpectedly, that is left set. Next time you start, windoze knows it has to check the file system on that partition/drive. I think what is happening that you are seeing is the disk gets spun up so the flags can be cleared indicating it was a clean shut-down (as opposed to power-fail etc.)

mikey

Mikey,

That is a logical explanation. I assume that if the drive decides to hibernate by itself - this is exactly what happens.

Next question is - would it not be nice to have such a timer function built in - into the OS?

The OS should already now be aware of any disk accesses and it could check the lack of disk activity, clear the dirty bit on the disk, and then command the disk to spin down, and leave it like that (if it has already spun down), when powering off the system... I think there is a way to command the disk to spin down, isn't there?

Probably not a thing we'll gonna see in WIN7+ soon - or ever??? So the answer to my original question is: no can do !!! We have to live with unnecessary wake-ups on power-downs.... argh...

Christian

Just a curiosity question, why does this matter?

"We have to live with unnecessary wake-ups on power-downs.... argh..."

Seriously? This is a big source of frustration?

I do have to admit that while I think the "dirty bit" thing is the issue, I have not lost any sleep over it :-) ... now if the drive starts making funny screeching noises, that tends to get my attention (or as my LInux machine did the other day, it seems all the bits fell off the platters (when I opened the drive, lots of little silver particles all over inside ... I suspect the missing bits :-) )

mikey

Those were only the ones. The zeros are obsidian.

Good point :-)

mikey

When I first installed Windows 7 I was annoyed if I left the computer for a few minutes that the next time I tried to do something in vegas, its monitor would freeze for about 10 seconds while the hard disk light was hard on. The rest of Vegas still seemed alive during this time. Eventually the problem went away.

Then came the time when I had to reinstall Windows 7 and the apps (I didn't have a proper image backup for some reason, or I couldn't find it). The freeze problem returned but after several weeks it seems to have disappeared once again.

Wouldn't it be nice to know what those little elves are doing in there?

John,

No, this is not a source of frustration, just a source of speculation about trying to understand why things are as they are :)

I'm close to a perfectionist when I design electronics, and hate to see non-perfect system design... Frankly speaking, this unnecessary starting of already idle disks is not prudent design :)

This unnecessary spinning up from zero-speed to full rpm, together with de- and re-parking of the data heads, causes always some extra wear and tear on the hard drive. One such cycle will shorten the life of your hard drive as much as many hours of running time.

To maximize the drive lifetime I opted to let unused drives spin down. What you gain of this spin down is probably lost, due to this unnecessary power-up of idle drives during system shutdown. This is my point and why I am speculating about the real benefits of letting disks spin down (disregarding the power savings).

I might change the drives back to run constantly. My info is quite old, but at least 10 years ago one disk start-up wear was considered to equal to running the disk for tens of hours. If this figure is still the same for modern drives - I don't know?! Someone else might have better information...

Speculating about such a minor detail could give the impression that I have not enough (video editing) to do. That is not true - render time must be filled with some other brain activities.... ;)

Cheers,

Christian

Caution - this is a guess and only a guess, but I have another theory on this. I suspect Windows powers up the inactive disks to speed up the shutdown process. In other words, it wants to be able to immediately read/write to any all system volumes - just in case an open program has that need. Part of that process may be to check the "dirty bit" or maybe a particular program wants to make a backup to inactive drive or whatever.

...Jerry

"This unnecessary spinning up from zero-speed to full rpm, ..."

I don't think you know that it's unnecessary. True, it might be, but we as end users are only speculating.

I never shut my drives down. I have drives in my server that have been running 24/7 for the last five or six years with no problems whatsoever.

All modern hard drives have fluid dynamic bearings so there is really nothing to wear out. Heat is the biggest cause of failure in drives, as long as the drives are kept cool you should have no trouble. The server and my editing machines are all in Antec 900 cases which have 120mm fans blowing fresh air directly through the drive cages, the drives are barely above room temperature. these cases also keep everything else cooled quite nicely as well.