Chapter 7 Storage

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

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

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

Storage Storage is nonvolatile where as RAM memory is volatile.

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

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

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

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

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

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 = 80 160 X Sectors per track = 18 2880 X Bytes per sector = 512 Total = 1,474,560 bytes

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

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

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

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

CDs and DVDs The parts disc label

CDs and DVDs The parts disc label laser diode

CDs and DVDs The parts disc label prism laser diode

CDs and DVDs The parts disc label lens prism laser diode

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

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

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

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

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

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

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

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

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

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-

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

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

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

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

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 12.25 MB per second These are the maximum speeds the rate can vary depredating on where the head is positioned on the disk

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

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

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

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

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

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”

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 100 years 500 years