secondary storage

WELCOME TO OUR PRESENTATIONTopic: Secondary Storage

Created by Hossain Raju

To get general idea about secondary storage.To obtain information concerning the advantages and disadvantages of secondary storage.To obtain general idea about types of secondary storage.To know the causes of using secondary storage.

OBJECTIVE OF THE PRESENTATIONCREATED BY HOSSAIN RAJU

CREATED BY HOSSAIN RAJU

OVERVIEWIntroductionWhat is Secondary Storage?The Advantages of Secondary Storage The Disadvantages of Secondary StorageEvolution of Secondary Storage DevicesTypes of Secondary StorageTypes of Optical DiskWhy we use Secondary Storage DevicesConclusionReferencesCreated by Hossain Raju


INTRODUCTIONEvery computer system consists of a variety of devices to store the instructions and data required for its operation. The instructions and data are stored in the memory (storage) unit of the computer. The memory components of a computer system can be divided into following main groups:Primary Storage (Main Memory),Secondary Storage (Auxiliary Memory), andInternal Processor Storage.Created by Hossain Raju


WHAT IS SECONDARY STORAGE?Secondary storage technology refers to storage devices and storage media that are not always directly accessible by a computer. This differs from primary storage technology, such as an internal hard drive, which is constantly available.

In Computer Science, Any means of storing and retrieving data external to the main computer itself but accessible to the program.


SECONDARY STORAGE (CONT)Used in a computer system to overcome the limitations of primary storage, Has virtually unlimited capacity because the cost per bit of storage is very low, Has an operating speed far slower than that of the primary storage, Used to store large volumes of data on a permanent basis,Also known as auxiliary memory.



THE ADVANTAGES OF SECONDARY STORAGE The advantages of Secondary storage are given below:Secondary storage devices are safe, reliable and permanent.High speed storage device.Huge volume data are stored.Less expensive.It is nonvolatile.



THE DISADVANTAGES OF SECONDARY STORAGEThe Disadvantages of Secondary storage are given below:While RAM electronic storage devices are fast, secondary storage devices are slower because they are electro-mechanical.The information on the secondary device has to be first located, then copied and moved to the primary memory or RAM.Takes more time.



EVOLUTION OF SECONDARY STORAGE DEVICESThe first hard drive was used in 1956 which is created by IBM and whose capacity was 5 MB.In 1971, IBM introduced a technology called the floppy disk, At the beginning of the 1980s the first optical devices were released by Sony and Philips. This drive can store approximately 650 to 700 of data.From 1990 to till now there are many devices is created like card reader, Memory Stick, Multimedia Card etc.Created by Hossain Raju


TYPES OF SECONDARY STORAGEThere are three main types of secondary storage:Magnetic Tape.Magnetic Disk.Optical Disk.



TYPES OF SECONDARY STORAGE (CONT)Magnetic Tape: Oldest storage device,Used for large computer like mainframe computers,Made of plastic coated with magnetic material,Store data permanently,Used to read and write data,Cost of storing data is expensive,Used in reels.



TYPES OF SECONDARY STORAGE (CONT)Magnetic Disk: A thin circular metal or plastic disk coated with magnetic material,Stored data in the form of magnetic spots,A random access device,Faster than magnetic tape.

There are three main types of magnetic disk:Hard DiskFloppy DiskZip Disk



TYPES OF MAGNETIC DISKHard Disk: Usually used as secondary storage,Also called fixed disk,Consists of one or more metal plates, Metal plates are coated with magnetic material to store data,Also have an access arm and read / write heads.



TYPES OF MAGNETIC DISK (CONT...)Floppy Disk: A small plastic plate coated with magnetic material,Stored data in magnetic spots,Used to transfer data from one computer to another.Created by Hossain Raju


Zip Disk : Similar to 3 inch floppy disk,Can store 100 MB or more data. Used to read and write data.

TYPES OF MAGNETIC DISK (CONT...)Created by Hossain Raju


TYPES OF SECONDARY STORAGE (CONT...)Optical Disk: Used LASER technology to read and write data, LASER stands for Light Amplification through Emission of Radiation,Laser beam writes on the surface of optical disk by creating very small holes. The presence of hole represents a One, and absence of the hole represents a Zero.


TYPES OF OPTICAL DISKThere are following main types of optical disk:CD-ROM.CD-R or WORMCD-RWDVD-ROMDVD-RDVD-RW



TYPES OF OPTICAL DISK (CONT)Created by Hossain Raju


WHY WE USE SECONDARY STORAGE DEVICESIt is non volatile and permanent.Used for a very simple task backing up data.Used to serve as an external hard drive.Becoming more and more portable as technology progresses.Many businesses will connect secondary storage devices to share files. Keep data on them for future use.Additional space for data.


CONCLUSIONThe primary memory is costly, not a permanent storage media and has limited capacity. The secondary memory is the storage other than main memory, and is used for storing large data files, system programs and the like which are not continuously required by the CPU. It also serves as an overflow memory when the capacity of the main memory is exceeded.Created by Hossain Raju


REFERENCESElements of Computer Science by S.K. Sarkar & A. K. Guptaen.wikipedia.orgwww.slideshare.netwww.techterms.comanswers.ask.com



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