(i). Disk Structure

Sectors

Tracks

Cylinders

A disk is accessed as an array: sector 0 is the first sector of the top track of the outmost cylinder. The next sectors of the same track are then ordered. Then, sectors from the next track are ordered. After all the sectors of all the tracks are ordered, we move to the next cylinder. The innermost is the last cylinder.

Disk drives are addressed as large 1-dimensional arrays of logical blocks, where the logical block is the smallest unit of transfer.

The 1-dimensional array of logical blocks is mapped into the sectors of the disk sequentially. Sector 0 is the first sector of the first track on the outermost cylinder.

Mapping proceeds in order through that track, then the rest of the tracks in that cylinder, and then through the rest of the cylinders from outermost to innermost.