Memory is an individuals capacity to learn something. In computer the basic function of memory is to hold the data, instructions, intermediate results and final results in the system so that it can deliver on demand at a later time. In simple words the memory is used to store data in the computer.
There are following types of memory :
(1) primary memory
(2) secondary memory
(3) cache memory
(4) virtual memory
(1) Primary memory :
The memory is also called us us primary memory. The primary memory is a part of the central Processing Unit. The primary memory is of two types :-
(1) Random Access Memory :
It is a read write memory I information can be read us well us writing into this type of memory. It is volatile temporary in nature IE the information ined in this memory is lost us soon as in the computer is switched off. It is of two types :-
(1) SRam (static Random Access Memory)
(2) dRam (dynamic Random Access Memory)
(2) Rom (Read Only Memory) :
The read only memory has the name my suggested contents informations that can only we read but cannot be written. The data storage in it is permanent in nature. It is a non-volatile permanent memory i. e. The data does not get e raised when the power is switched off. The Rom is of following types :-
- PROM (programmable read only memory)
- EPROM (eradual programmable read only memory)
- EPROM (Electrical Erasable Programmable read only memory)
- UVEPROM (Ultra Violet Erasable Programmable read only memory)
(2) Secondary memory :
Secondary storage refer to secondary storage device that can storage instructions and data permanently. The user can access the data form secondary memory. Whenever is required. The main storage device are floppy disks, hard disks, magnetic type, compact discs etc. These devices are used to store large amount of data.
Secondary storage devices are given below :
- Hard Disk Drive
- Floppy Disk
- Compact Disk
- Zip Drive
- Pen Drive
- Magnetic Tape
- DVD
Hard disk drive :
It is a secondary storage device. The hard disc is made of serval circular metal disk coated with magnetic ink. They are also called as magnetic disk each track is divided into different sectors. Vichar furtherb divided into bytes. The time taken to reach to the specified position is called as latency time.
At present we have following capacities hard disk -
- 40GB
- 80GB
- 120GB
- 160GB
- 320GB (By Imation Co.)
- 500GB
Hard Disk are available in Port wise -
(A) Pata Hard Disk
(B) Sata Hard Disk
RPM Wise, there are following HDD-
(A) 5400rpm
(B) 7200rpm
Floppy disc :
The floppy disk is a most popular portable baking storage device, which is used to store small amount of data, the maximum capacity is 1.44 MB of data in a 3.5" floppy (the floppy p is made up of malyar plastic. The floppy's are unreliable to as they are cumbersome to dust and heat.
Compact Disk :
CD stands for compact disk. The compact disc can store up to 700 to 800 MB of data. The CD are more reliable and have a better in data storage us compared to floppy A CD can Store 80 minutes of visual data. The CD's are rewriteable also.
Zip Drive :
It is also a store device. It has capacity of 100 MB. It is useful to store large file of offices.
Pen drive :
It is USB port device like us pen. It has storage capacity from 256 MB to 8GB.
Magnet Tape :
Magnet tape is one of the oldest for of computer storage. First and second generation computers is used magnet tape for most of their storage need. Today's magnet tap is not used often.
There are two type of magnet tapes. One consisting of a large real and the other small cartridge or cassette.
DVD :
DVD stands for digital versatile disc or digital video disk is popular optical disc storage media format its main uses are video and data storage. Most DVDs are of the same dimensions as CD (Compact Disk), but store more than 6 time as much data.