1. CHAPTER 6 66 Secondary Storage

2. 6 © The McGraw-Hill Companies, Inc. 2002 Objectives 1.Floppy and hard disks 2.Cartridges and disk packs 3.Performance enhancements 4.Compact disks 5.Specialized disks

3. 6 © The McGraw-Hill Companies, Inc. 2002 Secondary Storage Save information Permanent storage Temporary storage

4. 6 © The McGraw-Hill Companies, Inc. 2002 Floppy Disks Removable Write-protect Parts –Tracks –Sectors

5. 6 © The McGraw-Hill Companies, Inc. 2002 New Standards Zip Disks –250 MB SuperDisks –120 MB HiFD disks –200 MB

6. 6 © The McGraw-Hill Companies, Inc. 2002 Hard Disks Metallic disks Fast information Read-write heads Three types –internal hard disk –hard-disk cartridge –hard-disk pack

7. 6 © The McGraw-Hill Companies, Inc. 2002 Human hair dust particle fingerprint smoke particle disk head disk surface

8. 6 © The McGraw-Hill Companies, Inc. 2002 Internal Hard Disk Inside system unit Advantage over floppy disks Capacity: 80 gig

9. 6 © The McGraw-Hill Companies, Inc. 2002 Hard-disk Cartridges Easy removal Complements internal –JAZ from Iomega –SPARQ from SyQuest

10. 6 © The McGraw-Hill Companies, Inc. 2002 Hard-disk Packs Removable Massive storage capacity Common in mainframes Resembles stack of vinyl records

11. 6 © The McGraw-Hill Companies, Inc. 2002 Performance Enhancements Disk caching Redundant arrays of inexpensive disks (RAID) File compression and decompression

12. 6 © The McGraw-Hill Companies, Inc. 2002 Compact Permanent storage Laser beams reflect off pits Three types Optical Disks

13. 6 © The McGraw-Hill Companies, Inc. 2002 CD-ROM Compact disc-read- only memory Not written to 650 MB capacity

14. 6 © The McGraw-Hill Companies, Inc. 2002 CD-R & CD-RW CD-Recordable or WORM CD-RW or rewritable optical discs

15. 6 © The McGraw-Hill Companies, Inc. 2002 CD-R for Music Download from Internet Arrange and play music Create custom CD-R or CD-RW

16. 6 © The McGraw-Hill Companies, Inc. 2002 DVD Digital Versatile Disk or Digital Video Disk Types –DVD-ROM –DVD-R –DVD-RAM or DVD-RW

17. 6 © The McGraw-Hill Companies, Inc. 2002 Magnetic Tape Fast, direct access Sequential access Storage and backup

18. 6 © The McGraw-Hill Companies, Inc. 2002 Streamers Backup tape for microcomputer Capacities range from 120 MB to 5 GB Digital audio tape (DAT)

19. 6 © The McGraw-Hill Companies, Inc. 2002 Reels Minicomputer and mainframe 1/2 inch wide and 1/2 mile long Stores 1600 to 6400 cpi* Run on magnetic tape drives or magnetic tape units

20. 6 © The McGraw-Hill Companies, Inc. 2002 A Look to the Future Near-field recording devices Holographic storage systems

21. 6 © The McGraw-Hill Companies, Inc. 2002