I have Windows 8 installed on PC, and another Windows 8 installed inside virtual computer. On virtual computer - without antivirus. In both cases, I see that OS intensively works with the hard disk at idle time. If I continue to work with computer, it stops this, and resumes later.

It looks like some background maintenance process, like hard disk scanning. What part of Windows 8 is responsible for this? Is it possible to remove/reduce this effect?