hard drive keeps reading/writing non-stop even when computer is idle?

Configure Windows Task Manager to show I/O read and write bytes for each process. Watch the numbers and determine which process(es) seem to be the worst offenders.

Windows 7, I assume?

I have found a big culprit: firefox. By default, under the bookmarks there is a folder that provides real time RSS feed of news, firefox will keeps looking for updates continuously. By deleting that RSS feed folder, I cut the HD churn by a lot. That's simple.

However, here is something more complicated: Firefox will write to different folders on the HDD whenever I go to a new webpage, and those writing keeps the HD churning. Some of those folders are:

c:users\xxx\appdata\roaming\mozilla\firefox

c:users\xxx\appdata\local\mozilla\firefox

c:users\xxx\appdata\local\temp

Following the directions of this link: http://www.symbian-freak.com/forum/viewtopic.php?f=27&t=42302

I downloaded a trial version of Superspeed Ramdisk and move the first two folders to the newly created ramdisk. That helps a lot. However since my system is win 7 x64, the ramdisk version that will work for x64 costs $80, and to be able to copy the data back to an image upon shutdown, I will have to shell out an additional $20 for another version. This seems very steep in price for an utility that I want to use to cut down HDD churn. I'll look for other alternatives.

The last folder c:users\xxx\appdata\local\temp, I was unable to move because windows explorer is using that folder and I can erase everything but one single file from it, therefore it's not empty (a prereq per the above link to move to ramdisk) So I haven't solved the HDD churn completely.

I'm honestly surprised that you find Firefox's disk usage noticeable. I don't.

Firefox accesses the disk every time you visit a webpage, because the page is downloaded to the cache, which is stored on disk. So this is expected behaviour; the computer isn't "idle" at all.

Normal disk I/O will definitely not shorten the lifespan of your hard drive.

Maybe I am overly sensitive to the sound of the HD I/O. I have the desktop tower sitting next to me on a table, and all those churning sound is kinda annoying to me (unlike the fan sound or HD spinning sound, which I can accept because they are constant hum) the di-da, da-da-da, di-di-di, da-di just drive me nuts.

You mentioned normal disk I/O will not shorten the lifespan of my HDD, but I thought all these churning sound is made by sudden mechanical movement, so wouldn't it be true that I can lengthen the HD lifespan by minimizing these movements?

Some drives have an acoustic management setting, which is mostly intended to make seek noises less audible, at the expense of performance. You might want to look into that (or just move the tower).

Yes, seeking is a mechanical motion, but I've never heard of anyone talking about it as a cause of wear. The seek servo is built to handle more or less continuous use. I would be more concerned about things like heat, vibration/shock, how often it's power cycled, and how lucky you are on any given day. I've had brand new drives fail after less than 12 hours of operation for no apparent reason, and I've had 14-year-old drives that were still working but I tossed out because they were too small to be useful. There are variations in reliability between brands and models of drives, but the bottom line is that you need to maintain backup copies of any important data, because you can't predict when a failure might occur.

There are reports that Windows Indexing Service and/or  Superfetch may cause the problem you describe. So you might want to turn those off and then reboot.

What's the rest of  "users\xxx\appdata\roaming..." ? If it's  winupd.exe, then there's a problem with the Windows updater service, which may cause problems.

And you may want to do a thorough malware scan because there's apparently a trojan that may be related to this issue.

Ron

most of the stuff under "roaming" is the firefox stuff, which I have managed to put them under control by ramdisk. The other stuff under c\user\appdata\loca\temp is mostly youtube video and similar "flashy" things. I have not been able to move that temp folder because window explorer is using it all the time. It seems that there are many folders that browsing action write to that I could only tackle the biggest offender. I am no expert in the computer field but it kind of got me thinking - why wouldn't all those cache files and temp files created during browsing be written to RAM, instead of HD by default? I honestly don't need most of these stuff on my HD after I finished browsing. I can understand this when RAM is limited, but with the latest generation of machines (I have 9GB RAM) there is an abundance of RAM sitting unused. I won't hesitate to give 1GB such for all these "temporary" stuff. Too bad the only viable option I can find (and it does not comprehensively solve all these problems I have) is a 3rd party software that will set me back $100.

To contribute further to the HD chrun:  there's the continuous C:$logfile, C:$bitmap and C:$MFT (master file table) - I assume the latter is probably essential but how do I turn off the logfile, and the indexing service and superfetch you mentioned permanently?

Stop indexing service and Disable superfetch 

You can probably turn off both at the same time by following the instructions at the superfetch link to launch services.msc and change the Startup Type for both indexing service and superfetch. Then exit and reboot. Do NOT change anything else in services.msc! :emotion-5:

Superfetch uses C:$MFT (master file table) and C:$bitmap

I don't guarantee disabling either/both of these will solve the problem. And if that doesn't help, you may want to re-enable them.

Ron