1. Chapter 7
Storage

2. Objectives
Discuss the various types of items that users store on computer media
Differentiate between storage devices and storage media
Describe the characteristics of a floppy disk drive
Describe the characteristics of a hard disk
Describe the characteristics of CDs and DVDs
Differentiate among CD-ROMs, CD-RWs, DVD-ROMs, and DVD+RWs
Identify the uses of tape
Discuss PC Cards and the various types of miniature storage media
Identify uses of microfilm and microfiche

3. Storage
Storage holds data, instructions, and information for future use
Consists of two parts
Storage Device
Storage Media

4. Storage
Capacity refers to the number of bytes (characters) a storage media can hold.
Kilobyte (KB)
1 thousand
Megabyte (MB)
1 million
Gigabyte (GB)
1 billion
Terabyte (TB)
1 trillion
Petabyte (PB)
1 quadrillion
Exabyte (EB)
1 quintillion
Zettabyte (ZB)
1 sextillion
Yottabyte (YB)
1 septillion

5. Storage
Storage is nonvolatile where as RAM memory is volatile.

6. Storage Reading Writing Storage Devices
Hardware that records and retrieves items to and from storage media
Reading
Process of transferring items from storage media to memory
Writing
Process of transferring items from memory to storage media

7. Storage
Access Time
Time it takes storage device to locate item on storage medium
Time required to deliver item from memory to processor

8. Storage Access Time Access speed as it relates to storage media
Primary Storage
Secondary Storage
Slow
Fast
Items waiting to be interpreted and executed by the processor
Memory (most RAM)
Operating system, application software, user data and information
Hard Disk
Software, backups, movies, music
CDs and DVDs
Digital pictures or small files to be transported
Miniature Storage Media
Backups
Tape
Small files to be transported
Floppy Disk

9. Storage – Floppy Disk
Portable, inexpensive storage medium (also called diskette)
shutter
shell
liner
magnetic coating
metal hub
flexible thin film

10. Storage – Floppy Disk
The floppy disk magnetically coated disk is divided into tracks and sectors.
Track A narrow recording band that forms a full circle on disk
Sector
An individual piece of the wedge shaped division of all of the track. Each sector stores 512 bytes of information

11. Storage – Floppy Disk Determining a disk’s storage capacity
Multiply number of sides, number of tracks, number of sectors per track, and number of bytes per sector
For a Floppy
Sides = 2 X
Tracks = X
Sectors per track = X
Bytes per sector = 512
Total = 1,474,560 bytes

12. Storage – Zip Disks
Magnetic medium that stores 100 MB to 750 MB of data
Zip disk
Used to back up and to transfer files
Zip disks require a Zip drive —high capacity drive that reads from and writes on a Zip disk
External Zip drive

13. Storage – Hard Disks
High-capacity storage consisting of several inflexible, circular platters that store items electronically
Components enclosed in airtight, sealed case for protection

14. Storage – Hard Disks Three types of hard disks Internal External
Removable

15. CDs and DVDs
Flat, round, portable metal discs made of metal, plastic, and lacquer
Can be read only or read/write
Most PCs include CD or DVD drive, most play audio CDs

16. CDs and DVDs
The parts
disc label

17. CDs and DVDs
The parts
disc label
laser diode

18. CDs and DVDs
The parts
disc label
prism
laser diode

19. CDs and DVDs
The parts
disc label
lens
prism
laser diode

20. CDs and DVDs The parts disc label lens prism light- sensing diode
laser diode

21. CDs and DVDs The parts disc label pit lens prism light- sensing diode
laser diode

22. CDs and DVDs The parts disc label pit land lens prism
light- sensing diode
laser diode

23. CDs and DVDs How it works
Step 1. Laser diode shines a light beam toward disc
disc label
pit
land
lens
prism
light- sensing diode
laser diode

24. CDs and DVDs How it works
Step 2. The light passes through the prism and is focused by lens on to the metal layer of the disc.
disc label
pit
land
lens
prism
light- sensing diode
laser diode

25. CDs and DVDs 1 How it works
Step 3. If light strikes a land, it is reflected off the prism into the light sensing diode.
disc label
pit
land
lens 1
This represents a 1 in binary
prism
light- sensing diode
laser diode

26. CDs and DVDs 1 How it works
Step 4. If light strikes a pit, it is scattered and no light reaches the light sensing diode
disc label
pit
land
lens 1
This represents a 0 in binary
prism
light- sensing diode
laser diode

27. CDs and DVDs Data stored on a CD or DVD
single track spirals to edge of disc
disc sectors

28. CDs and DVDs Proper care of a CD or DVD
Do not expose the disc to excessive heat or sunlight
Do not eat, smoke, or drink near a disc
Do not touch the underside of the disc
Do not stack discs
Store disc in a jewel box when not in use
Hold disc by its edges

29. CDs and DVDs CD’s are available in variety of formats CD-ROM CD-R
CD-RW
DVD-ROM
DVD-R
DVD-RW+
DVD-RW-

30. CDs and DVDs A CD-ROM You cannot erase or modify contents
Commonly used to distribute software and games

31. CDs and DVDs
CD-R (compact disc-recordable) Compact disc onto which you can record text, graphics, and audio
Write on CD-R using CD burner (recorder) or CD-R drive and special software
CD-R drive can read and write both audio CDs and standard CD-ROMs

32. CDs and DVDs
CD-RW (compact disc-rewritable) Erasable disc you can write on multiple times
Must have a CD-RW disc, CD-RW software, and CD-RW drive
In many cases a CD-RW can not be read in a standard CD drive

33. CDs and DVDs
DVD-ROM (digital video disc-ROM) are high capacity compact disc capable of storing from 4.7 GB to 17 GB
Must have DVD-ROM drive or DVD player to read DVD-ROM
The DVD contains two layers of pits where lower layer is semitransparent
This gives your four sides for storage
DVD+RW is a rewritable DVD

34. 40X 40 X 150 KB per second = 6,000 KB per second or 6 MB per second
CDs and DVDs
The data transfer rate of a CD-ROM drive is the number of MB that can be transferred each second.
40X 40 X 150 KB per second = 6,000 KB per second or 6 MB per second
75X 75 X 150 KB per second = 11,250 KB per second or MB per second
These are the maximum speeds the rate can vary depredating on where the head is positioned on the disk

35. Tape
Tape storage uses a magnetically coated ribbon of plastic capable of storing large amounts of data and information at a low cost
Primarily used for backup

36. PC Cards Credit-card-sized device commonly used in notebook computers
Adds capabilities to computer
PC Cards
Category Thickness Use
Type I 3.3 mm RAM, SRAM, flash memory
Type II 5.0 mm Modem, LAN, SCSI, sound, TV turner, hard disk, or other storage
Type III 10.5 mm Rotating storage such as a hard disk

37. Miniature Mobile Storage Media
Common types of miniature mobile storage media
Compact Flash
Smart Media
Secure Digital
Memory Stick
Microdrive
xD Picture Card

38. Miniature Mobile Storage Media
Card Reader
Reads information stored on miniature mobile storage media

39. Miniature Mobile Storage Media
Smart card
Stores data on microprocessor embedded in small card
Input, process, output, and storage capabilities

40. Microfilm and Microfiche
Store microscopic images of documents on a roll or a sheet of film
Images recorded using a computer output microfilm (COM) recorder
Microfilm
Uses a 100- to 215-foot roll of film
Microfiche
Uses a small sheet of film, usually 4” x 6”

41. Microfilm and Microfiche
Life expectancies of various storage media
Media Type Guaranteed Potential
Life Life
Expectancy Expectancy
Magnetic Disks 3 to 5 Years 20 to 30 years
CD’s and DVD’s 5 to 10 Years 50 to 100 years
Microfilm years years