Cylinder. A group of all the tracks on all the magnetic platters of a hard disk that can be accessed without moving the magnetic head. Access to the data inside one cylinder is much faster than moving the head from one cylinder to another.
Disc. A non-magnetic storage media (compact disc, CD-RW or DVD).
Disk. A magnetic storage media (floppy disk or hard disk). (Note: Disc and Disk are often used interchangeably.)
Drive. A general word that can mean both a device for accessing information on a disk (floppy disk drive) and a partition that can be accessed from an operating system (logical drive).
File. A file is named information storage in the file system. In different file systems, files can be stored in different ways, with different file names and different ways to write the full path to the file in the folder tree.
File allocation table (FAT). The hard disk area, located after the boot sector, which describes physical files locations; a duplicate for higher data storage reliability follows FAT.
The FAT also contains the disk cluster list, as well as many records as there are clusters on a disk. If a FAT cell contains «0», the cluster is empty. The last file cluster, defective cluster and reserved clusters have their own special markings.
The FAT describes each file by a chain of numbers — like serial numbers of a file’s disk clusters. The number of the first cluster of each file is stored in the folder. Writing, deleting and modifying files and folders results in corresponding FAT changes.
File system. Data structure that is necessary to store and manage files. A file system does the following functions: tracks free and occupied space, supports folders and file names, tracks the physical positions of files on the disk. Each partition may be formatted with its own file system.
Folder. A table in the file system that contains a description of files and other folders. Such a structure allows creation of a folder tree that begins with the root folder.
Formatting. The process of creating a service structure on the disk. There are three levels of hard disk formatting: low-level (marking the magnetic surface with tracks and sectors), partitioning and high-level (creation of a file system on a partition).
Hard disk (hard drive). Fixed storage media along with integrated electronics that consists of several magnetic platters that rotate synchronously on one spindle. Hard disks have relatively high capacity and high read/write speed.
Hard disk geometry. A set of hard disk parameters that usually includes the number of cylinders, heads and sectors per track.
Head (magnetic head, read/write head). A hard disk consists of several magnetic platters; for each side of each platter, there is a head that is used to read and write information on it.
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