Fundamental storage technologies
Most commonly used data storage technologies are semiconductor, magnetic, and optical, while paper still sees some limited usage. Some other fundamental storage technologies have also been used in the past or are proposed for development.
1. Magnetic storage media
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.
In modern computers, magnetic storage will take these forms:
In modern computers, magnetic storage will take these forms:
• Magnetic disk
1.Floppy disk, used for off-line storage
2.Hard disk drive, used for secondary storage
• Magnetic tape data storage, used for tertiary and off-line storage
The typical optical disc, stores information in deformities on the surface of a circular disc and reads this information by illuminating the surface with a laser diode and observing the reflection.
2. Optical storage media
Optical disc storage is non-volatile. read/write media). The following forms are currently in common use:
• CD, CD-ROM, DVD, BD-ROM: Read only storage, used for mass distribution of digital information (music, video, computer programs)
• CD-R, DVD-R, DVD+R, BD-R: Write once storage, used for tertiary and off-line storage
• CD-RW, DVD-RW, DVD+RW, DVD-RAM, BD-RE: Slow write, fast read storage, used for tertiary and off-line storage
• Ultra Density Optical or UDO is similar in capacity to BD-R or BD-RE and is slow write, fast read storage used for tertiary and off-line storage.
3.Semiconductor storage media
Semiconductor memory uses semiconductor-based integrated circuits to store information. A semiconductor memory chip may contain millions of tiny transistors or capacitors. Both volatile and non-volatile forms of semiconductor memory exist. In modern computers, primary storage almost exclusively consists of dynamic volatile semiconductor memory or dynamic random access memory. Since the turn of the century, a type of non-volatile semiconductor memory known as flash memory has steadily gained share as off-line storage for home computers. Non-volatile semiconductor memory is also used for secondary storage in various advanced electronic devices and specialized computers.
4. Magneto-optical disc storage media
Magneto-optical disc storage is optical disc storage where the magnetic state on a ferromagnetic surface stores information. The information is read optically and written by combining magnetic and optical methods. Magneto-optical disc storage is non-volatile, sequential access, slow write, fast read storage used for tertiary and off-line storage.
Activity
Classify storage devices according to the categories given below.
1 magnetic Media
2 Optical media
