22. disk drive geometry

• What does the term disk drive geometry mean in connection with the hard disk drives?

  • geometry describes disk drive

  • the number of cylinders (actually, tracks/surface), surfaces (read/write heads), and sectors/track

  • These numbers, together, are called the CHS geometry -- cylinders, heads, and sectors

  • The sector size is generally 512 bytes, so the calculation:

        C * H * S * 512
    

    yields the disk drive capacity.

  • The actual CHS value is limited by the bit size of the C, H, S data fields.