SECONDARY STORAGE
The data and instructions in RAM are purely temporary in nature and they are erased automatically as soon as the power is switched off. The secondary storage is used to store the data permanently. The user can access the data from secondary storage whenever required. The secondary storage devices offer huge storage volumes with high speed and reliability.
The various types of secondary storage are:
A storage medium, in which different patterns of magnetization are used to represent stored bits or bytes of information, is called magnetic storage. Magnetic storage consists of :
Magnetic tapes provide a compact and inexpensive method of storing data and programs. Magnetic tapes are mainly used for backup of data. The main features of a magnetic tape are:
The various types of secondary storage are:
- Magnetic storage
- Optical storage
- Solid state storage
A storage medium, in which different patterns of magnetization are used to represent stored bits or bytes of information, is called magnetic storage. Magnetic storage consists of :
- Magnetic tapes
- Magnetic disks
Magnetic tapes provide a compact and inexpensive method of storing data and programs. Magnetic tapes are mainly used for backup of data. The main features of a magnetic tape are:
- Magnetic tape is half-inch wide tape of Mylar material, coated with magnetic material.
- Magnetic tapes have much higher data transfer rate and are preferred for high-speed applications.
- Magnetic tape is as same as playing an audio cassette in a tape recorder. Whenever we like to hear a particular song from an audio cassette, we need to rewind or forward the tape for that particular song.
- Data is stored as binary digits (i.e. 0 and 1) in magnetic tape, which represents the presence and absence of magnetic field.
MAGNETIC DISKS
Magnetic disks are the most popular medium of data storage in these days. It is like a gramophone record, which is made up of plastic like material called Mylar. The main features of a magnetic disk are:
On the basis of read/write mechanism, the magnetic disks are classified into two types:
Floppy disk is one of the most popular data storage medium, used for permanent data storage and data transfer before the invention of compact disks. The floppy disk was introduced by IBM in 1972. Floppy disk basically consists of a round, flat piece of plastic, coated with a magnetic material.
The main features of a floppy disk are:
Magnetic disks are the most popular medium of data storage in these days. It is like a gramophone record, which is made up of plastic like material called Mylar. The main features of a magnetic disk are:
- The data is stored in the same way as in magnetic tape.
- The read/write heads are small electromagnets that are capable of reading, writing data and erasing the data stored in the form of magnetic spots.
- Data is randomly stored and retrieved from these disks i.e. the drive can access any portion of data directly.
On the basis of read/write mechanism, the magnetic disks are classified into two types:
- Floppy disk/Removable disk.
- Hard disk/Fixed disk.
Floppy disk is one of the most popular data storage medium, used for permanent data storage and data transfer before the invention of compact disks. The floppy disk was introduced by IBM in 1972. Floppy disk basically consists of a round, flat piece of plastic, coated with a magnetic material.
The main features of a floppy disk are:
- The two principal sizes or dimensions of floppy disks are 3.5 inch and 5.25 inch.
- Floppy disks are portable i.e. we can easily carry this storage device from one place to another for data storage.
- Floppy disks are slower to access than hard disks and have less storage capacity.
HARD DISK/FIXED DISK
Hard disk is another type of magnetic disk on which we can store data and information permanently. IBM (International Business Machine) invented hard disk in 1957. Initially, they were called fixed disks and later they were named hard disks.
A hard disk contains a number of platters of aluminum coated with magnetic material. Each of these platters is divided into tracks and sectors. All the platters are arranged on a spindle. This spindle is attached to a motor that can rotate at a speed of 5600 rotations per minute or 7200 rpm. The main features of hard disk are:
Hard disk is another type of magnetic disk on which we can store data and information permanently. IBM (International Business Machine) invented hard disk in 1957. Initially, they were called fixed disks and later they were named hard disks.
A hard disk contains a number of platters of aluminum coated with magnetic material. Each of these platters is divided into tracks and sectors. All the platters are arranged on a spindle. This spindle is attached to a motor that can rotate at a speed of 5600 rotations per minute or 7200 rpm. The main features of hard disk are:
- Hard disk stores more data than floppy. Its storage capacity comes in Gigabyte and now also in Terabytes. (1 TB=1024 GB)
- Hard disk stores the data permanently.
- To store data on hard disks, it should be formatted. Formatting is a process of creating tracks an d sectors on the surface of hard disk so that the data can be stored.
- Hard disks are enclosed in a sealed container. The hard disk in a non-removable form of storage device but nowadays removable hard disk is also available.
OPTICAL STORAGE
With the advancement in technologies, such type of storage devices came in the market, which has more storage capacities and used optical or light technology, to store or retrieve the data. These kinds of storage devices are known as optical storage devices.
TYPES OF OPTICAL STORAGE
A CD-ROM is a round disk coated with very thin reflective layer of aluminum. CD-ROM has a spiral track of data from inside to outside direction of the disk. The main features of a compact disk are:
With the advancement in technologies, such type of storage devices came in the market, which has more storage capacities and used optical or light technology, to store or retrieve the data. These kinds of storage devices are known as optical storage devices.
TYPES OF OPTICAL STORAGE
- CD-ROM (Compact disk read only memory)
- DVD (Digital versatile disk or Digital video disk)
A CD-ROM is a round disk coated with very thin reflective layer of aluminum. CD-ROM has a spiral track of data from inside to outside direction of the disk. The main features of a compact disk are:
- It is capable of storing large amounts of data. A typical CD can store data unto 700 MB.
- The vendor stamps CD-ROM's and once stamped, they cannot be erased or filled with new data.
- To read a compact disk, you need a CD-ROM player. We can load any type of CD into any CD-ROM player.
- CD-ROM player also known as a CD-ROM drivers a device that can read information from CD-ROM.
- Compact disk is more reliable than floppy disk and higher data processing speed than floppy disk.
DVD (DIGITAL VERSATILE/VIDEO DISK) /DVD-ROM
DVD is a new type of CD-ROM that can hold the data minimum of 4.7 GB and maximum of 17 GB. Today, DVD are now replacing audio, video, and data CD's. A DVD has a layered structure and extremely high data density, which makes it capable of storing up to 17 GB in a single disk. DVD-ROM uses the same principle as that used in CD-ROM for reading and writing data. Some of the main features of DVD are:
DVD is a new type of CD-ROM that can hold the data minimum of 4.7 GB and maximum of 17 GB. Today, DVD are now replacing audio, video, and data CD's. A DVD has a layered structure and extremely high data density, which makes it capable of storing up to 17 GB in a single disk. DVD-ROM uses the same principle as that used in CD-ROM for reading and writing data. Some of the main features of DVD are:
- DVD-ROM drives are used to read data from a DVD.
- A new device, called as COMBO DRIVE is also capable of reading DVD-ROM as well as CD-ROM and it can also write or rewrite data on a CD-ROM.
- DVD-WRITER is also a new device, capable of reading as well as writing on a CD-ROM and DVD-ROM.
SOLID STATE STORAGE
Solid State Storage is one of the latest secondary storage devices. This type of storage is also called Flash memory. It is a permanent storage device i.e. data will not be erased even when the power is switched off.
TYPES OF SOLID STATE STORAGE
It is a compact device of the size of a pen comes in various shapes and stylish designs and may have different storage capacities. The main features of flash drive/pen drive are:
Solid State Storage is one of the latest secondary storage devices. This type of storage is also called Flash memory. It is a permanent storage device i.e. data will not be erased even when the power is switched off.
TYPES OF SOLID STATE STORAGE
- Flash Drive (Pen Drive)
- Memory Card
It is a compact device of the size of a pen comes in various shapes and stylish designs and may have different storage capacities. The main features of flash drive/pen drive are:
- It enables easy data transmission from one computer to another.
- It is a plug and play device that simply plugs into a USB port of a computer. The computer detects it automatically as a removable drive.
- We can easily read, write, copy, delete or move data from the computer's hard disk drive to pen drive and vice versa.
- It has very compact size and very low energy consumption.
- It stores data permanently. i.e. non-volatile in nature.
- Its available storage capacities are 512 MB, 1 GB, 2 GB, 4 GB, 8 GB, 16 GB and 32 GB etc.
MEMORY CARD (SD/M MC)
- A memory card or flash card is an electronic flash memory data storage device used for storing digital information.
- Some of the most popular ones are Secure Digital (SD) and Multimedia Memory Card (M MC). Storage capacity of these cards range from 64 GB to 8 GB normally.
- They are commonly used in many electronic devices, including digital cameras, mobile phones, laptop computers, MP 3 players,and video game consoles.
- They are small, record able, and they retain data without power.
Write by Ditender Singh and
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