Secondary Storage
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Secondary Storage






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Secondary Storage Secondary Storage Presentation Transcript

  • OBJE C TIVE OF THE PRE SE NTA TION 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. CREATED BY HOSSAIN RAJU
  • OVERVIEW Introd uction What is Second ary Storage? C reated by H ossain Raju The Ad vantages of Second ary Storage The D isad vantages of Second ary Storage Evolution of Second ary Storage D evices Types of Second ary Storage Types of O ptical D isk Why we use Second ary Storage D evices C onclusion References
  • INTRODUCTIONEvery com puter system consists of a variety of d evicesto store the instructions and d ata required for its Created by H ossain Rajuoperation. The instructions and d ata are stored in them em ory (storage) unit of the com puter. The m em orycom ponents of a com puter system can be d ivid ed intofollowing m ain groups:  Prim ary Storage (M ain M em ory),  Second ary Storage (Auxiliary M em ory), and  Internal Processor Storage.
  • WHAT IS SECONDARY STORAGE?Second ary storage technology refers tostorage d evices and storage m ed ia thatare not always d irectly accessible by acom puter. This d iffers from prim arystorage technology, such as an internalhard d rive, which is constantly available.In C omputer Science, “Any m eans ofstoring and retrieving d ata external to them ain com puter itself but accessible tothe program .”
  • SECONDARY STORAGE (CONT…) U sed in a com puter system to overcom e the lim itations of prim ary storage, Created by Hossain Raju H as virtually unlim ited capacity because the cost per bit of storage is very low, H as an operating speed far slower than that of the prim ary storage, U sed to store large volum es of d ata on a perm anent basis, Also known as auxiliary m em ory.
  • THE ADVANTAGES OF SECONDARYSTORAGEThe ad vantages of Second ary storage are given below: Created by Hossain Raju Second ary storage d evices are safe, reliable and perm anent. H igh speed storage d evice. H uge volum e d ata are stored . L ess expensive. It is nonvolatile.
  • THE DISADVANTAGES OF SECONDARYSTORAGEThe D isad vantages of Second ary storage are given below: While RAM electronic storage d evices are fast, second ary Created by Hossain Raju storage d evices are slower because they are electro- m echanical. The inform ation on the second ary d evice has to be first located , then copied and m oved to the prim ary m em ory or RAM . Takes m ore tim e.
  • EVOLUTION OF SECONDARY STORAGE DEVICES The first hard d rive was used in 1 956 which is created by IBM and whose capacity was 5 M B. In 1 971 , IBM introd uced a technology called the floppy d isk, Created by Hossain Raju At the beginning of the 1 980s the first optical d evices were released by Sony and Philips. This d rive can store approxim ately 650 to 700 of d ata. From 1 990 to till now there are m any d evices is created like card read er, M em ory Stick, M ultim ed ia C ard etc.
  • TYPES OF SECONDARY STORAGEThere are three m ain types of second ary storage: Created by Hossain Raju M agnetic Tape. M agnetic D isk. O ptical D isk.
  • TYPES OF SECONDARY STORAGE (CONT…)Magnetic Tape: O ld est storage d evice, Created by Hossain Raju U sed for large com puter like m ainfram e com puters, M ad e of plastic coated with m agnetic m aterial, Store d ata perm anently, U sed to read and write d ata, C ost of storing d ata is expensive, U sed in reels.
  • TYPES OF SECONDARY STORAGE (CONT…)Magnetic Disk: A thin circular m etal or plastic d isk coated with m agnetic m aterial, Created by Hossain Raju Stored d ata in the form of m agnetic spots, A rand om access d evice, Faster than m agnetic tape. There are three m ain types of m agnetic d isk: i. H ard D isk ii. Floppy D isk iii. Zip D isk
  • TYPES OF MAGNETIC DISK Hard Disk: Created by Hossain Raju U sually used as second ary storage, Also called fixed d isk, C onsists of one or m ore m etal plates, M etal plates are coated with m agnetic m aterial to store d ata, Also have an access arm and read / write head s.
  • TYPES OF MAGNETIC DISK (CONT...) Floppy Disk: A sm all plastic plate coated with Created by Hossain Raju m agnetic m aterial, Stored d ata in m agnetic spots, U sed to transfer d ata from one com puter to another.
  • TYPES OF MAGNETIC DISK (CONT...) Zip Disk : Sim ilar to 3 ½ inch floppy Created by Hossain Raju d isk, C an store 1 00 M B or m ore d ata. U sed to read and write d ata.
  • TYPES OF SECONDARY STORAGE(CONT...) Optical Disk: U sed L ASER technology to read and write d ata, L ASER stand s for L ight Am plification through Em ission of Rad iation, L aser beam writes on the surface of optical d isk by creating very sm all holes. The presence of hole represents a O ne, and absence of the hole represents a Zero.
  • TYPES OF OPTICAL DISKThere are following m ain types of optical d isk:ii. C D -RO M . Created by Hossain Rajuiii. C D -R or WO RMiv. C D -RWv. D VD -RO Mvi. D VD -Rvii. D VD -RW
  • TYPES OF OPTICAL DISK (CONT…) Created by Hossain RajuC D-ROM :Stand s for C om pact D isk-Read O nlyM em ory, D ata stored can only be read ,D ata can be easily transferred ,C om m only can store 650 M B / 700 M B/750 M B d ata.
  • TYPES OF OPTICAL DISK (CONT…) C D-R (C D Recordable) Or Created by Hossain Raju WORM:  C om pact d isc record able,  An optical second ary storage d evice,  Invented by Sony and Philips,  Also known as a WO RM (write once read m any),  C an store d ata on it only once.
  • TYPES OF OPTICAL DISK (CONT…) C D-RW ( C D Rewritable ): Created by Hossain Raju Stand s for C om pact D isk Rewritable, Special type of C D , C an write d ata on it, C D -Writers are used to store d ata.
  • TYPES OF OPTICAL DISK (CONT…) DVD - Digital Video Disk (DVD- Created by Hossain Raju ROM): Stand s for D igital Vid eo D isk, U sed a laser beam with a short wave length C reate very sm all holes on the surface of d isk. C an store up to 1 7 GB or m ore d ata.
  • TYPES OF OPTICAL DISK (CONT…)DVD-R (DVD-Recordable): Created by Hossain RajuStand s for D igital Vid eo D iskRecord able,Initially a blank d isk,C an store d ata only once,Becom es read only,N orm ally used to store high d efinitionvid eo m ovies.
  • TYPES OF OPTICAL DISK (CONT…) Created by Hossain Raju DVD-RW ( DVD Rewritable): Stand s for D igital Vid eo D isk Rewritable. C an write d ata m any tim es by erasing the old d ata.
  • WHY WE USE SECONDARY STORAGE DEVICES It isnon volatile and perm anent. U sed for a very sim ple task backing up d ata. U sed to serve as an external hard d rive. Becom ing m ore and m ore portable as technology progresses. M any businesses will connect second ary storage d evices to share files.  K eep d ata on them for future use. Ad d itional space for d ata.
  • CONCLUSIONThe prim ary m em ory is costly, not a perm anent storagem ed ia and has lim ited capacity. The second ary m em ory Created by Hossain Rajuis the storage other than m ain m em ory, and is used forstoring large d ata files, system program s and the likewhich are not continuously required by the C PU . It alsoserves as an overflow m em ory when the capacity of them ain m em ory is exceed ed .
  • REFERENCES Elem ents of C om puter Science by S.K . Sarkar & A. K . Gupta Created by Hossain Raju en.wikiped www.slid www.techterm