Do disk partitions help when performing multiple maintenance tasks?

Related to my earlier BSOD thread, I decided to run an Avira antivirus scan on my C drive in administrator mode and a scandisk with error fixing on my games partition. What surprised me is that Avira took over 35 minutes to scan a .lnk file in my user directory while the scandisk is still ongoing even though I expected it to finish in 25-30 minutes.

I take it this is normal behaviour for a HDD under stress? I've also been experiencing lockups for 5-10 minutes after which the system restores itself. My RAM and processor usage are well below 50% and I'm using winamp and firefox in addition to these 2 maintenance tasks.

 

The answer to your subject is NO.

Were you running both the AV scan and the scandisk at the same time? DON'T DO THAT!

I think you need to understand how a hard drive works. There are the spinning platters that contain the data, and then there is one "head" which is used to read the data from the platters. Because there is only one head, the disk can only do ONE thing at a time, period. The disk can break up multiple tasks and do them each in little parts, but each of those parts can only happen by itself.

When you ask for data on one part of the platter, the head must be moved to that part of the disk, then the data is read or written, then the next request can be processed, and the head must be moved again. Every time the head moves it takes time. If you are trying to do too many things at once, the disk will spend more time moving the heads around than actually doing anything useful.

By running an AV scan and a scandisk, you couldn't have chosen two worse things to run at the same time. Each of those things moves the head across the entire disk, and running them at the same time would cause massive slowdowns.

Also, normally those operations are safe to run, but doing them both at the same time also increases the possibility that the disk will fail, due to heat or other mechanical failure.

Multiple partitions on the disk can even make this worse, because all of the data is on the same patters, and the head must be moved between both areas of the platter.

If you need to run an AV scan or scandisk (or defrag, or video/mp3 conversion, etc...) only do one at a time.

 

Thanks for that, 101 lesson on hard drive for the idiot I am. Fortunately both tasks completed safely sometime during my sleep so I won't do it again.