[S.O.A.D.A.]

Hello,

It's a new XP installation, runs pretty smoothly.
I've noticed, an hour ago, that the HD light is constantly on, it's not even flickering. Touched the box - there really seems to be constant HD activity. I ain't running anything that's supposed to cause this (like a scan or a defrag). What could it be? How can I monitor disk activity and, more importantly, which programs generate the disk IO on Windoze?

Thanks,
SOADA

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How can I monitor disk activity and, more importantly, which programs generate the disk IO on Windoze?

Task Manager will tell you if some process is running. As for the disk IO... I'm not sure what you're asking. If you're referring to the bus, then "everything" in Windows generate usage on the bus. If you're asking what will cause the light to be on, then you might be misunderstanding what the light actually does... it's not really monitoring the hard drive usage, its showing activity on the bus. For instance, if you have SATA CD/DVDROMs installed, they will also cause activity on the bus, and also cause the led to blink. Now why the led is always on is another question. Does it "never" turn off?

[makai]

How can I monitor disk activity and, more importantly, which programs generate the disk IO on Windoze?

Task Manager will tell you if some process is running. As for the disk IO... I'm not sure what you're asking. If you're referring to the bus, then "everything" in Windows generate usage on the bus. If you're asking what will cause the light to be on, then you might be misunderstanding what the light actually does... it's not really monitoring the hard drive usage, its showing activity on the bus. For instance, if you have SATA CD/DVDROMs installed, they will also cause activity on the bus, and also cause the led to blink. Now why the led is always on is another question. Does it "never" turn off?

[S.O.A.D.A.]

I thought the led meant disk reads/writes were taking place. This has been consistent with my experience. If I'm watching a movie from CD the CDROM led will blink. The HD led does not represent CDROM IO.

I have SATA II HDs & IDE DVDROMs.

Does it "never" turn off?

No, it just stayed on without blinking. I rebooted and the problem (if that's indeed what it was) went away.

SOADA

[makai]

I thought the led meant disk reads/writes were taking place... <snip>... The HD led does not represent CDROM IO.

True for IDE, not true for Sata. The led is monitoring the bus, not the hard drive. This stumped me the first time I ran into this too. I thought something was wrong with a new motherboard I had until I read up on it. It can be disabled if you disable Autorun on the CD/DVDROm, but you lose the functionality.

Not sure what could have been the cause for your problem, but if its working now, its just something to watch over.

[S.O.A.D.A.]

True for IDE, not true for SATA

You mean, if the CDROM is on IDE its IO will not cause the led to blink, but if it's on SATA it will? And if I disable autorun then CDROM activity will not cause the led to blink? BTW - if there is activity on the BUS, then the device connected to it is performing R/W operations, right? So it's kinda the same, isn't it?

I think if I add, in Task Manager, the columns "I/O Read Bytes" & "I/O Write Bytes" it will give me an idea on disk activity generated by each process. I guess I could do the same in Process Explorer, which I personally like much better - it has, I think, also I/O Delta, which makes it easier to asses that activity in real time.

[makai]

You mean, if the CDROM is on IDE its IO will not cause the led to blink, but if it's on SATA it will? And if I disable autorun then CDROM activity will not cause the led to blink?

Yup!

BTW - if there is activity on the BUS, then the device connected to it is performing R/W operations, right?

Not necessarily... Autoplay is a "monitor" waiting for something to happen. The activity is because every so often, it pings the bus. Apparently with Sata CD/DVDROMS, this pinging happens about every second. Read up on Google.

I think if I add, in Task Manager, the columns "I/O Read Bytes" & "I/O Write Bytes" it will give me an idea on disk activity generated by each process. I guess I could do the same in Process Explorer, which I personally like much better - it has, I think, also I/O Delta, which makes it easier to asses that activity in real time.

Whatever bakes your cookies!

[S.O.A.D.A.]

....and puts milk on my table : )

Thanks for your help, mate.
Another grain of knowledge to the windmills of my mind....

SOADA

Edited by S.O.A.D.A., 04 October 2009 - 01:30 AM.