1. Storage Devices Powered by DeSiaMore1

2. Contents Storage Primary Secondary Access Method Floppy disk Hard disk Optical disks Magnetic media Powered by DeSiaMore2

3. Overview Information storage For future To share To modify Permanent Storage secondary storage, nonvolatile Temporary storage RAM volatile Powered by DeSiaMore3

4. Secondary Storage 1.Secondary storage provides permanent or non-volatile storage: 2.This is accomplished by writing files to and reading from the secondary storage device. Writing- Is the process of serving information to the secondary storage device. Reading- Is the process of accessing information from secondary storage. Powered by DeSiaMore4

5. Characteristics of Secondary Storage devices Media or medium which is the actual physical material that holds the data and programs Capacity measures how much a particular storage medium can hold Storage device are hardware that reads data and programs from storage media. Most also write to storage medium Access speed or access time measures the amount of time required by the storage devices to retrieve data and program. Powered by DeSiaMore5

6. Storage devices can be categorized as magnetic or optical Magnetic storage are such as diskettes, hard disk, high capacity floppy disks, and magnetic tapes Optical storage are compact disks CD-ROM, DVD- ROM, CD-R, CD-RW etc Categories of Storage Devices Powered by DeSiaMore6

7. Floppy Disks Floppy disks are often called diskettes or simply disks. They are portable and removable storage media They use flat circular pieces of Mylar plastic that have been coated with magnetic material. Powered by DeSiaMore7

8. Traditional Floppy Disk Traditional floppy disks: 1.44MB 3.5 inch 2HD-two side high density Powered by DeSiaMore8

9. How a Disk Drive Works Metal shutter Hard plastic jacket Label Write protection notch in the open position Powered by DeSiaMore9

10. Hard Disks Metallic disks Composed of metallic rather than plastic disks Fast information storage and retrieval (write and read) Read-write heads Powered by DeSiaMore10

11. Materials that can cause a head crash Powered by DeSiaMore11

12. Internal Hard Disk Inside system unit for storing the operating system, other programs and large data files. Motor with access arm and read- write heads. Many advantages over floppy disks. Capacity (up to thousands times a single floppy) Speed (twenty times the speed) Powered by DeSiaMore12

13. Hard-Disk Packs Removable, massive storage capacity Common in mainframes Resembles stack of record albums Powered by DeSiaMore13

14. Optical disks use laser technology. CD and DVD are optical disk formats. Compact, high capacity form of permanent storage Laser beam writes by creating a pattern of pits (holes) and lands (flat areas) to encode data bits Laser beams reflect off the pits and lands to read the data Optical Disks Powered by DeSiaMore14

15. CD-ROM Compact disc-read-only memory Not written to 650 MB capacity Powered by DeSiaMore15

16. CD-R & CD-RW CD-Recordable or WORM ( write once, read many) CD-RW or rewritable optical discs Powered by DeSiaMore16

17. DVD Digital Versatile Disk or Digital Video Disk Up to 4.7 gigabytes a capacity, seven times CD DVD-ROM- provide high quality, movie length videos DVD-R- consumer recordable version DVD-RAM or DVD-RW- rewritable version of 2.6 to 5.2 GB storage capacity Powered by DeSiaMore17

18. Magnetic Tape Disks offer fast, direct access to data programs Tapes offer sequential access (fast forwarded or rewound) Storage and backup Forms of tape storage are: Magnetic tape streamers Magnetic tape reels Powered by DeSiaMore18

19. Backup tape cartridge units used with microcomputer systems Capacities range from 120 MB to 5 GB Magnetic Tape Streamers Powered by DeSiaMore19

20. Magnetic Tape Reels Used with minicomputer and mainframe computers Often 1/2 inch wide and 1/2 mile long Stores 1600 to 6400 characters per inch Tapes are run on magnetic tape drives or magnetic tape units Powered by DeSiaMore20