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What applications are exactly reading/writing my HDD in a given period? Application for statistics?

I can leave my computer for an hour and come back and the disk light is running full-bore. I sign on and the Process Explorer icon shows the CPU running about 30%. But of course, before I can actually check to see what it's doing the activity stops (other than the interminable paging activity needed to make the system "live" again). (It's like the teenager who hides the page he's viewing when you walk into the room.)

Is there a (free) tool (for Windows Vista) that maintains a circular journal of what's going on -- say, a snapshot taken once a minute for several hours -- so I can figure out what it's doing. (And, no, this isn't to monitor what my teenagers are doing -- they're both in their 30s now.)

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marked as duplicate by Bob, Canadian Luke, studiohack May 20 '12 at 16:10

This question was marked as an exact duplicate of an existing question.

Often antivirus scanners, defragmenters, backup software, etc. may be set to run when the computer is idle. Any one of those could cause high disk usage. Dave's suggestion of the Resource Monitor should work. – Bob May 20 '12 at 12:35
Have a look in the event log - this may give you some idea of what's happening. As others have suggested it's probably disk defrag, indexing or a virus scan. – BJ292 May 20 '12 at 13:49
@BJ292 -- Indexing is turned off, disk defrag is not set to run automatically, virus scan doesn't admit to doing anything. – Daniel R Hicks May 20 '12 at 13:51
I'd still start with the event log (system & applications), after that have a look at all the active tasks in task scheduler and see when they last ran. – BJ292 May 20 '12 at 14:04
Sigh, once again the point is missed and "exact duplicate" is used to excuse the ignorance. Well, I didn't really expect any better (though I was hoping). – Daniel R Hicks May 20 '12 at 19:11

Do you have Skype running? It can become a "supernode" and that will create a great deal of traffic. Torrent clinets could also do this. Backup utilities like WD Smartware are a possibility as well. Malware infection?

3D screen savers can use a great deal of resources as well

You can start resource monitor(Perfmon.exe) and record some activity to identify the app.

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Skype's not running, stock screen saver, indexing disabled. There is, obviously, an AV package running, but hard to tell what it's doing when, without some instrumentation. And it appears to me that most tools like Perfmon can't be made to journal activity over periods of hours (if they journal at all, vs giving a snapshot of current activity). – Daniel R Hicks May 20 '12 at 13:11

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