1. Data on the disk is recorded on tracks, which are concentric rings on the platter around the spindle.
2. The tracks are numbered, starting from zero, from the outer edge of the platter.
3. The number of the tracks per inch on the platter measures how tightly the tracks are packed on a platter.
4. Data on the physical disk can be divided into tracks, then it can be explained as follows.
5. Each track is divided into smaller units called sectors.
6. A sector is the smallest, individually addressable unit of storage.
7. The track and sector structure is written on the platter by the drive manufacturer using a formatting operation.
8. The number of sectors per track varies according to the specific drive.
9. The first personal computer disks had 17 sectors per track.
10. Recent disks have a much larger number of sectors on a single track.
11. There can be thousands of tracks on a platter, depending on the physical dimensions and recording density of the platter.
12. Typically, a sector holds 512 bytes of user data, although some disks can be formatted with larger sector sizes.
13. In addition to user data, a sector also stores other information, such as sector number, head number or platter number, and track number.
14. This information helps the controller to locate the data on the drive, bu storing this information consumes space on the disk.
15. There is a difference between the capacity of an unformatted disk and a formatted one.
16. Drive manufacturers generally advertise as being 500GB will only hold 465.7GB of user data, and the remaining 34.3GB is used for metadata.
17. A cylinder is the set of identical tracks on both surfaces of each drive platter.
18. The location of drive heads is referred to by cylinder number, not by track number.
Access Time Characteristics:
1. The access time or response time of a rotating drive is a measure of the time it takes before the drive can actually transfer data.
2. The factors that control this time on a rotating drive are mostly related to the mechanical nature of the rotating disks and moving heads.
3. It is composed of a few independently measurable elements that are added together to get a single value when evaluating the performance of a storage device.
4. The access time can vary significantly, so it is typically provided by manufacturers or measured in benchmarks as an average.
5.SSD's this time is not dependent on moving parts, but rather electrical connections to solid-state memory, so the access time is very quick and consistent.