4330666777777-computer-applications.pptx

Secondary memory uses

1. WELCOME TO OUR PRESENTATION Topic: Secondary Memory Presented By : Presented To : JONSHU ARYA Ms. Sonal Anand ARUN BALHARA AADITYA KAKKAR ANURAG SANJAY HONEY GOEL

2. Introduction What is Secondary Memory? The Advantages of Secondary Memory The Disadvantages of Secondary Memory Evolution of Secondary Memory Devices Types of Secondary Memory Types of Optical Disk Why we use Secondary Memory Devices Conclusion OVERVIEW

3. Introduction Every 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 Memory (Main Memory), Secondary Memory (Auxiliary Memory), and Internal Processor Memory .

4. What is Secondary Memory? Secondary memory technology refers to storage devices and storage media that are not always directly accessible by a computer. This differs from primary memory 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.”

5. Secondary Memory Used in a computer system to overcome the limitations of primary memory, 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 memory, Used to store large volumes of data on a permanent basis, Also known as auxiliary memory.

6. The Advantages of Secondary Memory The advantages of Secondary Memory are given below: Secondary memory devices are safe, reliable and permanent. High speed storage device. Huge volume data are stored. Less expensive. It is nonvolatile.

7. The Disadvantages of Secondary Memory The Disadvantages of Secondary memory are given below: While RAM electronic storage devices are fast, secondary memory 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.

8. Evolution of Secondary Memory The 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 till now there are many devices created like card reader, Memory Stick, Multimedia Card etc.

9. Types of Secondary Memory There are three main types of secondary memory: Magnetic Tape. Magnetic Disk. Optical Disk.

10. Types of Secondary Memory 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.

11. Types of Secondary Memory 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 Disk Floppy Disk Zip Disk

12. Types of Magnetic Disk Hard 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.

13. 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.

14. Types of Magnetic Disk (cont...) Zip Disk : Similar to 3 ½ inch floppy disk, Can store 100 MB or more data. Used to read and write data.

15. 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.

16. Types of Optical Disk There are following main types of optical disk: CD-ROM. CD-R or WORM CD-RW DVD-ROM DVD-R DVD-RW

17. Types of Optical Disk (cont…) CD-ROM : Stands for Compact Disk-Read Only Memory, Data stored can only be read, Data can be easily transferred, Commonly can store 650 MB / 700 MB/ 750 MB data.

18. Types of Optical Disk (cont…) CD-R (CD Recordable) Or WORM: Compact disc recordable, An optical secondary storage device, Invented by Sony and Philips, Also known as a WORM (write once read many), Can store data on it only once.

19. Types of Optical Disk (cont…) CD-RW ( CD Rewritable ): Stands for Compact Disk Rewritable, Special type of CD, Can write data on it, CD-Writers are used to store data.

20. Types of Optical Disk (cont…) DVD - Digital Video Disk (DVD-ROM): Stands for Digital Video Disk, Used a laser beam with a short wave length Create very small holes on the surface of disk. Can store up to 17 GB or more data.

21. Types of Optical Disk (cont…) DVD-R (DVD-Recordable): Stands for Digital Video Disk Recordable, Initially a blank disk, Can store data only once, Becomes read only, Normally used to store high definition video movies.

22. Types of Optical Disk (cont…) DVD-RW ( DVD Rewritable): Stands for Digital Video Disk Rewritable. Can write data many times by erasing the old data.

23. Why we use Secondary Storage Devices It 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.

24. Conclusion The 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.

25. References Elements of Computer Science by S.K. Sarkar & A. K. Gupta en.wikipedia.org www.slideshare.net www.techterms.com answers.ask.com

26. Thank you