secondary storage devices

What is secondary storage?

A secondary storage device store the data permanently for the future uses. The primary memory holds data as long as the computer is switched on. But when computer  switched off then all the work and data lost. So, retrieve and preserve the data in future we need a storage media that can holds data permanently. For instance: floppy disk, hark disk, USB pen drive etc.

 

secondary storage devices types

secondary storage devices

1. Magnetic tape

Magnetic tape is most popular secondary storage device which is being widely used. It was used in old tape recorder where data can stored and read easily in  sequential manner. 

Magnetic tape is coated with Metal oxide material on its base surface. The tape ribbon contains rills or small catteries. Plastic ribbon was used in the magnetic tape which  size is about 2 cm or 1.25 cm.

secondary storage devices

Data are recorded on the  tape in the form of small invisible magnetize or non magnetize spot. Generally, it is completely coated from one side either on 7-track or 9-track method.

This spots represent the data on the ribbon surface. The read/write head is use to place data or access the data and able to store MP3, Video etc. files for long periods of time. These data can erase and re-stored according to need.

2. Hard disk

A hard disk is use to store massive amount of information. Hard disk is also called fixed disk. The data and programs are stored on this disk can be access at very high speed I.e. rotating speed is about 3600 - 7200 rotation/minutes. Now, It is capable to store huge data like 2 TB, and  4 PETA. 

secondary storage device

It is best for personal computer which is not simply can be  remove from computer and read/write speed is also very reasonable. Basically it is combination of disks and divided into tracks and sector. It is more stable and being rigid placed into dust free environment and more faster than many secondary storage device. 

3. Floppy disk

Floppy disk was introduce about in 1972. This  is just like thin flexible plastic disk. It is also called as flexible disks or diskettes because this is thin flexible plastic disk. 

It comes in various shape and size that  offers to record the data either on single side or double side I.e. you can store the data and information on one side or even you can store the data on the both sides.

secondary storage devices

Floppy disks are also divided into track and sector where data and program are stored. It is placed in square cover which provides protection from dust or particles.

 It also consists of a wiping head to wipe the surface dust.  It normally comes in  size of  about 3-4 inches in diameter . Sometimes  around 8 inches diameter are used in big computer.

4. Magnetic disk

Magnetic disks are most popular direct access secondary storage device. A disk is combination of 6 or more thin circular plate/platter which is coated on both sides. These plates are organized in central hub that rotates or spans the disk at speed of 60 or more revolution/second. 

The data are recorded on the disk in the form of magnetize or non-magnetize of tiny invisible spots on the surface. The new data and information on the magnetic tape cab be read, write or erase many times on the same location. 

Disks are  divided into tracks and tracks are subdivided into sector. These tracks and sector are used to access the information or store the information. there are two type of head writer.

1. Moving head unit - Head moves horizontally over each tracks and one head for each surface

2. Fixed head unit  - Only one head unit for all tracks hence this access data very fast.

5. Winchester disk

A windcheater disk consists of multiple plates, which is mounted over the single central hub. It contain a read/write head use to place and take off from the surface  of the disk.

This is coated with something like lubricant that reduce the friction on the surface. It is fixed type of drive i.e. platters and disk drive are sealed together  that can not be separate from each other. This result the Winchester disk in limited storage capacity. 

The technology and advancement in the windcheater made possible to increase the number of tracks in the surface of Winchester disk. The storage capacity are enhanced from it's previous version which is more reliable, updated, and able to fast access the data or programs.

6. Optical disk

Optical disk is very recently introduced, which is a very popular as secondary storage device. It is popular because of it's portability and simplicity to read/write. It is capable to store large amount of data i.e. more than a zip disk or floppy disks.

For example: CD-ROM ( Compact Disk read-only memory). It contains a single silver rotating disk which is coated with thin film of aluminum and other recording materials but,

 Plate is made up of plastic. This reflects the laser beam of CD-ROM. The data or program are recorded using the leaser beam technology on the surface of the disk.

The disk plates are divided into tracks and sectors where data are recorded or accessed. The major advantage of the optical disk is that it is much affordable and not very expensive. To read  the data light leaser beam is focused over the plate.  

Type of optical disk

The technology in the development of optical disk have been growing day by day. A number of various differences can be found in earlier optical device and in the recent optical devices. So let's quickly see the types of optical disk.

a. CD-ROM 

b. CD- RW 

c. WORM 

d. DVD

CD-ROM

CD-ROM stands for Compact Disk Read Only Memory. It  appear just like as single circular plate which is coated with shiny silver color. It is made up of Poly-carbonate plastic and thin layer of pure aluminum is applied to make the more reflation surface. 

secondary storage devices

It is capable to hold data 650 MB to 700 MB. It only can read the data and program form the disk. The data are written with the help of Optical rays i.e. data recorded on the disk by optical disk as well as data accessed also with optical rays reflation. 

These are designed in various shape and size like round, oval, triangle etc. The stored data can be read or access permanently but never can be modify.

CD-RW

CD-RW stands for Compact Disk Read Write memory. A CD-RW is very similar to WORM which data can write multiple times and can access those data. This  is considered that CD-RW is the advance format of CD-ROM. This is more capable, more advance, fast access and higher storage capacity.

It uses the laser beam technology in order to store the data on track and sector. It offer to erase it's contents and write the completely fresh  data again I.e. it provides facility to reuse the storage device.

WORM 

WORM stands for Write Once Read Many. WORM assists user to create their own disk using CD-R. Which can be easily access by CD-drive which is attached  with computer system as peripheral devices. Generally, it's traditional appearance is more like standard CD-ROM. 

Once the data are recorded on the disk, can be access those data for ever but data only possible to write at once.

DVD

DVD full form is Digital Versatile Disc or Digital Video Disc.  It use the same same technology as CD-R. The major difference between CD-R and DVD is higher storage capacity. The data and information are recorded with the help of  laser beam technology.

secondary storage devices

Today it is very popular to carry the software driver and Bootable ISO for different Operating system. almost every electronic equipment which need driver, supply with DVD disk.

This is quite a long article but, we have tried to make you understand the different type of secondary storage device, which is useful for the every computer students in exam purpose and knowledge purpose also. What you know about secondary storage device according to you let us know.