Definition | hard disk – hard disk

The hard disk is a magnetic medium for digital data storage. Hard disk is different from RAMRAM” From’the computer, whose data is erased when the latter is turned off. Hard disk storage is permanent and has a much higher capacity (up to several terabytes). Hard disk drives are found in computers, but also in recorders DVD or video game consoles. It can be internal or external.

How does a hard disk work?

One hard disk Contains multiple discs in . format Aluminium or glass (called trays) covered with a thin layer of Material magnetism, on which data is written Digital. after Electric current By passing through the read head, the data is encoded in the form of bits (1 or 0). The read head begins writing data at the periphery of the disk, and then gradually advances towards the center. To read the data, the reading head detects the direction of the magnetic field

Hard disk properties

  • coordination : Expressed in inches, it indicates the size of the magnetic plates. The 2.5-inch format is most popular for internal hard drives, while the larger 3.5-inch format is for desktop computers.
  • access protocol : Relates to connectors and cables used to route data. since the 2000s, sata (Serial ATA) is the most widely used.
  • Ability : Expressed in bytes, it indicates the amount of data that can be copied to the hard disk.
  • Transfer rate (the flow): indicates the amount of data that can be read or written to disk per unit time and is expressed in bits per second.
  • Rotational Speed : Expressed in revolutions per minute, it stands for rotation speed Magnetic disks around the central axis. The higher it is, the faster the writing and reading speed, but the more it is consumedenergy It tends to heat the material. Standard is 5400 rpm for a 2.5-inch external hard drive and 7200 rpm for a 3.5-inch external hard drive.
  • interface : For external hard disk, it refers to the transfer medium between the hard disk and the computer. Most hard drives work with a USB 2.0 or USB 3.0 interface, but there are also interfaces fire wire or Thunderbolt.
  • file system : Represents the way files are stored and retrieved (directories and subdirectories). The most famous of them are FAT32, exFat and NTFS. Note that the system can be changed by formatting the disk on your computer.

Today’s traditional hard disk drives tend to be replaced by hard disk drives SSD, which acts as a file portable memory It is much faster, more compact and less sensitive to shock due to the lack of components mobile phones.

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