Where does the physical information of HD( cylinder, Head, sectors) will be found in system.

Hard disk - Wikipedia, the free encyclopedia (http://en.wikipedia.org/wiki/Hard_drive)

This shows some good information about hard disk drives that is easy to understand.

I don't completely understrand your question, but hopefully it will be answered in there.
If you're asking where the data is actually stored, then it is stored on the disc itself (in the link above, there are many pictures of the insides of a hard drive, the disk is the circular (disc shaped) part, this comprises many sectors.

These discs are called platters.