Magnetic Storage Devices

Information Magnetic storage uses different patterns of magnetization on a magnetically coated surface to store information. Magnetic storage is non-volatile. The information is accessed using one or more read/write heads which may contain one or more recording transducers. A read/write head only covers a part of the surface so that the head or medium or both must be moved relative to another in order to access data. In modern computers, magnetic storage will take these forms:
  • Magnetic disk
    • Floppy disk, used for off-line storage
    • Hard disk drive, used for secondary storage
  • Magnetic tape data storage, used for tertiary and off-line storage

In early computers, magnetic storage was also used for primary storage in a form of magnetic drum, or core memory, core rope memory, thin-film memory, twistor memory or bubble memory. Also unlike today, magnetic tape was often used for secondary storage.
What Is a Magnetic Storage Device?
One of the common aspects of modern computer hardware is a technology known as a magnetic storage device. This is a technology available in multiple forms, such as a floppy disk drive, a tape drive and a hard drive.

Magnetic Storage Basics A magnetic storage device works on a principal of magnetic charge. The basic premise is that a magnetizable medium, such as a metal wire, can be magnetized by an electric magnet. It can then be "read" magnetically and its recorded "data" played back.

Audio Recording Magnetic storage was first used for audio recording, and is generally referred to as magnetic recording. The basic principle is the same. Modern audio recording often uses a digital magnetic storage device.

Digital Recording A digital magnetic storage device records (stores data) in a stepped pattern. This is because a digital signal consisting of only two main states. A digital stream of data is as a binary signal containing a sequence of 1's and 0's, so only two magnetic states are necessary.

Magnetic Storage Devices A magnetic storage device is a device that uses a magnetic head to read and write data to and from a magnetizable medium. The medium can be as basic as a plastic tape that is coated with fine particles of a metal, such as is found in audio recording and tape storage devices.

Types of Magnetic Storage Devices There are many types of magnetic storage devices. Audio tape is an early example of magnetic recording that later transitioned into use for computer data storage. A computer's hard disk is a more modern example of magnetic data storage. A floppy disk is yet another example.

Sample Exam Question A PC incorporates a hard disk, a CD-R drive and a DVD-RW drive. Describe three ways in which the hard disk will be used.[6]

1._
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2.
_
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3._
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Answer
To store user data
. . . ‘permanently’/when the computer is switched off/for future access
[1] for each of two points

To store application software
. . . from where it will be loaded into RAM to be executed/where SW is
installed
[1] for each of two points

To store the ‘non-core’ of the operating system
. . . from where it will be loaded into RAM to be executed
[1] for each of two points

[2] for each of three ways [6]