Disk Structure
There is no structure to a disk except cylinders and sectors, anything else is up to the OS.
The OS imposes some structure on disks.
Each disk contains:
- 1. data: e.g., user files
- 2. meta-data: OS info describing the disk structure
For example, the free list is a data structure indicating which disk blocks are free. It is stored on disk (usually) as a bit map: each bit corresponds to one disk block.
The OS may keep the free list bit map in memory and write it back to disk from time to time.