Will stopping hard disk when inactive also stop downloads?

Functionally, this setting is useless when the computer only has one hard drive. Windows will not spin down the OS drive unless the whole machine is going to sleep.

Wes Sayeed

Posted 2015-09-10T17:47:31.973

Reputation: 12 024

Except if you are running Windows 95 by any chance. I cannot comment on newer versions. – musiKk – 2015-09-10T19:40:04.007

@Wes Sayeed, I do not believe your following statement to be true: Windows will never spin down the OS drive. Please provide a reference. – Steven – 2015-09-10T21:15:57.093

2No reference; just personal experience. I work with computers for a living and I have never been able to get Windows to spin down the primary OS drive. I don't know if this is by design or if it's a consequence of access patterns, but if you set the spin-down time to 1 minute, disable all other power management features, and then let the machine sit idle, the drive never spins down. – Wes Sayeed – 2015-09-10T21:29:16.807

1From personal experience, the OS drive spun down, and restarted when there was I/O activity, on Windows 98 and 98SE. I also can't comment on newer versions of Windows. – alephzero – 2015-09-10T22:34:44.303

Why does everybody keep referencing Windows 95/98 behavior? That was literally 20 years ago! – Wes Sayeed – 2015-09-10T22:41:38.640

2@alephzero Can confirm this also was true in Windows 3.1. Source: me, who once tweaked 3.1 to to power down the hard drive maximum battery life on the last B&W laptop made by caching a minimum set of DLLs so disk wouldn't be touched until I hit "save". – Michael – 2015-09-10T23:08:52.910

@WesSayeed If you meant "in the currently supported versions of Windows," you shouldn't have written "never". – alephzero – 2015-09-10T23:16:45.727

The basic code is the same that Windows will power down disks due to inactivity but the problem is there are far too many programs wanting to do stuff so it won't in my opinion unless you have data drives that aren't so frequently accessed. – netniV – 2015-09-10T23:38:11.503

@alephzero It should go without saying. I shouldn't have to spell that out for every pilkunnussija on the Internet.

– Wes Sayeed – 2015-09-11T00:41:48.070

1@netniV there's no reason why "doing stuff", especially when the user isn't actively at the machine, should result in frequent disk access. Nearly all reads done by a long-running background app should be served from cache, and writes can be deferred until the disk needs to be spun up anyway for a read, or memory pressure forces a page cache eviction. – hobbs – 2015-09-11T02:54:27.450

Every time I have run a disk monitor and seen the activity on an idle system, there is always a lot going on even when idle. Caching covers a lot but a program can even explicitly say don't use caching when using CreateFile thus is never cached. – netniV – 2015-09-11T06:48:11.050

@hobbs No reason? Imagine what loss of power would mean if the OS did not flush cached writes to disk regularly. So this is all by design and for good reason. Yeah, you can tweak cache flushing settings, so that the hard drive can spin down for hours at a time, but it comes with risk for the average user. – misha256 – 2015-09-14T20:02:44.717

Expected "simple" at the end of the answer :) – Krish – 2015-09-11T06:18:55.193

And that is why, in practice, you will likely never see the OS disk spin down - even when, seemingly, nothing is running. There are plenty of background services/processes that continuously read/write (even if just small amounts) and this will keep the drive awake day and night ;-) – misha256 – 2015-09-14T20:19:59.017

Will stopping hard disk when inactive also stop downloads?

Answers