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Outline7,8,9

By Bradley Dunn,2014-11-12 07:45
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Outline7,8,9

    Copyright: Louise Henry at GSU - CS

    Chapter 7: Storage

    Memory Versus Storage

    What is storage?

    ; Media and devices used to store and retrieve data, instructions, and information How does storage differ from memory?

    ; (Memory is also called primary storage or RAM)

    ; Storage (also called secondary storage):

    ; Stores items for future use, rather than temporarily

    ; Storage is nonvolatile, rather than volatile

    ; When you want to work with a file, you read it from storage and place it in memory ; When you are finished with the file, you write it from memory into storage How does volatility compare?

    ; Screen display and contents of most RAM (memory) erased when power is off ; Contents of storage retained when power is off

    What is a storage device and a storage medium?

    ; Storage device

    o Hardware that records and retrieves items to and from a storage medium ; Storage medium

    o Physical material on which a computer keeps data, instructions, and information What is reading and writing?

    ; Reading

    o Process of transferring data, instructions, and information from a storage medium into

    memory

    o Serves as a source of input

    ; Writing

    o Process of transferring items from memory to a storage medium

    o Serves as a source of output

    What is access time?

    ; Amount of time it takes device to locate item on disk

    ; Defines speed of disk storage device

    o Tape (slowest, least expensive)

    o Floppy Disk

    o Compact Disc

    Page 1 of 24

    o Hard Disk

    What is capacity?

    ; Number of bytes (characters) storage medium can hold

    o Kilobyte KB 1 thousand

    o Megabyte MD 1 million

    o Gigabyte GB 1 billion

    o Terabyte TB 1 trillion

    o Petabyte PB 1 quadrillion

    Floppy Disks

    What is a floppy disk?

    ; Portable, inexpensive storage medium

    ; Today’s standard disk is 3.5” wide

    ; HD (High Density disk) Stores 1.44MB

    What are the parts of a floppy disk?

    ; Thin, circular, flexible film enclosed between two liners How are floppy disk drives designated?

    ; One floppy drive

    o drive A

    ; Two floppy drives

    o drive A

    o drive B

    How does a floppy disk drive work?

    ; 1: Shutter moves to expose recording surface on disk ; 2: Signal sent to control movement of read/write heads and disk ; 3: If write instruction, circuit board verifies whether disk can be written to

    ; 4: Motor causes floppy disk to spin

    ; 5: Motor positions read/write heads over correct location on disk ; 6: Read/write heads read data from or write data on the floppy disk What are tracks and sectors?

    ; Track is narrow recording band that forms full circle on disk surface ; Sector can store up to 512 bytes of data

    o 80 tracks per side X 18 sectors per track X 2 sides per disk X 512 bytes per sector =

    1,474,560 bytes = 1.44 MB

    What is formatting?

    Page 2 of 24

; Process of preparing disk for reading and writing

    ; Formatting marks bad sectors as unusable

    How do you care for a floppy?

    ; Proper care helps maximize disk’s life

    ; Floppy disk can last at least seven years

    o Never open the shutter and touch the disk’s recording surface

    o Avoid exposure to heat and cold

    o Avoid exposure to magnetic fields

    o Avoid exposure to contaminants such as dust, smoke, or salt air

    o Keep disks in a storage tray when not using them What is a write-protect notch?

    ; Small opening with a cover that you slide

    ; Protects floppy disks from being erased accidentally

    o notch open means you cannot write on the disk

    o notch closed means you can write on the disk

    High-Capacity Disks

    What is a high-capacity disk drive?

    ; Uses disks with capacities of 100 MB and greater

    ; Primarily used to backup files and transfer files

    o Zip? drive

    o Uses a Zip? disk that can store 100 MB or 250 MB of data What is a backup?

    ; Duplicate of file, program, or disk that you can use if original is lost, damaged, or destroyed

    Hard Disks

    What is a hard disk?

    ; High-capacity storage (20 100 GB)

    ; Consists of several inflexible, circular platters that store items electronically

    ; Components enclosed in airtight, sealed case for protection How does a hard disk work?

    ; 1: Circuit board controls movement of head activator and small motor ; 2: Small motor spins platters

    ; 3: When software requests disk access, read/write heads determine location of data

    ; 4: Head actuator positions read/write head arms over correct location on platters to read or write data

    What is a cylinder?

    Page 3 of 24

; Location of a single track through all platters

    ; Single movement of read/write head arms can read same track on all platters What is a head crash?

    ; Occurs when read/write head touches platter surface

    ; Spinning creates cushion of air that floats read/write head above platter

    o clearance between head and platter is approximately two millionths of an inch

    o gap is half the diameter of a dust particle

    What is a disk cache?

    ; Portion of memory processor uses to store frequently accessed items What is a partition?

    ; Formatted hard disk divided into separate areas called partitions ; Each partition functions as if it were a separate hard disk drive ; Designation for first partition or for a single partition on hard disk

    o drive C

    ; Designation for second partition on hard disk

    o drive D

    What is a removable hard disk?

    ; Disk drive in which a plastic or metal case surrounds the hard disk so you can remove it from the

    drive

    ; Used for backup or to transfer files

    How does RAID work?

    ; Disk system that duplicates data, instructions, and information to improve data reliability ensuring

    that data is not lost if one drive fails

    o Mirroring has one backup disk for each disk

    o Striping stores data across multiple disks

    What Windows utilities maintain a hard disk drive?

    ; Backup

    ; Disk Cleanup

    ; Disk Defragmenter

    ; Scheduled Tasks

    What is an Internet hard drive?

    ; Service on Web that provides storage to computer users

    o Most offer free storage

    o Revenues come from advertisers

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What are advantages of an Internet hard drive?

    ; Large audio, video, and graphics files can be downloaded to an Internet hard drive instantaneously

    ; Files can be accessed from any computer or device with Web access ; Others can be authorized to access data from your Internet hard drive ; Allows offsite backups of data

    Compact Discs

    What is a compact disc (CD)?

    ; Storage medium

    ; Most PCs include some type of compact disc drive ; Available in variety of formats

    o CD-ROM

    o CD-R

    o CD-RW

    o DVD-ROM

    ; DVD+RW

    How do you use a compact disc?

    ; CD drives can read compact discs, including audio discs How does a laser read data on a compact disc?

    ; 1: Laser diode shines light beam toward compact disc ; 2: If light strikes pit, it scatters. If light strikes land, it is reflected back toward laser diode.

    ; 3: Reflected light deflected to light-sensing diode, which sends digital signal of 1. Absence of

    reflected light read as digital signal of 0.

    How is data stored on a compact disc?

    ; Typically stores items in single track

    ; Track divided into evenly sized sectors that store items ; Single track spirals to edge of disc

    What is a jewel box?

    ; Protective case for compact disc

    How should you care for a compact disc?

    CD-ROMs

    What is a CD-ROM?

    ; Compact disc that uses same laser technology as audio CDs for recording music

    ; Cannot erase or modify contents (can only be read) ; Typical CD-ROM holds about 650 MB

    Page 5 of 24

; Commonly used to distribute software and games

    What is the data transfer rate of a CD-ROM drive?

    ; 40X

    o 40 X 150 KB per second = 6,000 KB per second or 6 MB per second ; 75X

    o 75 X 150 KB per second = 11,250 KB per second or 12.25 MB per second CD-R and CD-RW

    What is a CD-R (compact disc-recordable)?

    ; Compact disc onto which you can record text, graphics, and audio ; Write on CD-R (only once) using CD burner (recorder) ; CD-R drive can read and write both audio CDs and standard CD-ROMs ; Cannot erase disc’s contents

    What is a 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 How is an audio CD created?

    DVD-ROMs

    What is a DVD-ROM (digital video disc-ROM)?

    ; High capacity compact disc capable of storing from 4.7 GB to 17 GB (telephone book for USA)

    ; Must have DVD-ROM drive or DVD player to read DVD-ROM ; Primarily used for movies

    ; Next-generation software will be delivered on DVD

    How does a DVD-ROM store data?

    ; Two layers of pits are used, where lower layer is semitransparent

    o Laser can read through it to upper layer

    ; Bits are closer together

    ; Can be double-sided

    ; DVD+RW is a rewritable DVD (similar to CD-RW)

    ; 4.7 GB 17 GB

    Tapes

    What is tape?

    ; Magnetically coated ribbon of plastic capable of storing large amounts of data and information at a

    low cost

    ; Primarily used for backup

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What is sequential access versus direct access?

    ; Sequential access

    o Reading and writing data consecutively

    o Method used for tape

    ; Direct access

    o You can locate a particular data item or file immediately

    o Method used for floppy disks, hard disks, and compact discs

    o Also called random access

    Enterprise Storage Systems

    What is an enterprise storage system?

    ; Strategy that focuses on availability, protection , organization, and backup of storage in a company

    o RAID

    o Tape Library

    o CD-ROM jukeboxes

    PC Cards

    What are uses of PC Cards?

    ; Used for notebook and mobile computing:

    o Type I RAM, flash memory

    o Type II Modem, Sound

    o Type III Hard disk

    Miniature Mobile Storage Media

    What is miniature mobile storage media?

    ; Handheld devices use to augment internal storage

    o Memory Card

    o Memory Stick

    How is miniature storage media used?

    ; Handheld devices, such as players and wallets, read or display contents of miniature storage media

    such as memory cards

    ; Digital cameras

    ; Notebook computers

    ; Cellular telephone

    What is a smart card?

    ; Stores data on thin microprocessor embedded in credit card

    What are the types of smart cards?

    Page 7 of 24

; Intelligent smart card contains processor and has input, process, output, and storage capabilities

    ; Memory card has only storage capabilities

    o Store data such as photographs, music, books, and video clips

    o Store a prepaid dollar amount that is updated when the card is used

    o Store patient records, vaccination data, and other healthcare information

    o Store tracking information such as customer purchases or employee attendance

    What is electronic money?

    ; Means of paying for goods and services over the Internet ; Also called e-money or digital cash

    Microfilm and Microfiche

    What are 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

    o Microfilm

    ; Uses a 100- to 215-foot roll of film

    o Microfiche

    ; Uses a small sheet of film, usually 4” x 6”

    ; Reduces paper

    ; Inexpensive

    How do life expectancies of various media compare?

    ; Microfilm/Microfiche longest life expectancy

    Summary

    What are suggested storage devices for the Home user?

    ; 3.5-inch HD floppy disk drive

    ; 250 MB Zip? drive

    ; 40 GB hard disk

    ; Internet hard drive

    ; CD-ROM drive

    ; CD-RW/DVD drive

    What are suggested storage devices for the SOHO user?

    ; 3.5-inch HD floppy disk drive

    ; 60 GB hard disk

    ; Internet hard drive

    ; CD-ROM drive

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; CD-RW/DVD drive

    ; 20 GB Peerless drive What are suggested storage devices for the Mobile user? ; 3.5-inch HD floppy disk drive ; 10 GB hard disk

    ; 1 GB PC Card hard disk ; Internet hard drive

    ; CD-RW/DVD drive

    What are suggested storage devices for the Large Business user? ; 3.5-inch HD floppy disk drive ; 80 GB hard disk

    ; CD-ROM drive

    ; CD-RW/DVD drive

    ; Microfilm or microfiche ; Smart card reader

    ; RAID

    ; Tape drive

    ; Enterprise storage system What are suggested storage devices for the Power user? ; 3.5-inch HD floppy disk drive ; DVD+RW drive

    ; 100 GB hard disk

    ; CD-ROM drive

    ; Internet hard drive

    ; 20 GB Peerless drive

Chapter 7 Complete

    Page 9 of 24

    Chapter 8: Systems Software

    Composed of Operating System and Utility Programs

    Operating Systems

    What is an operating system (OS)?

    ; Set of programs that coordinates all activities among computer hardware resources

    What are the functions of an operating system?

    ; start up the computer

    ; administer security

    ; control a network

    ; access the Web

    ; monitor performance and provide housekeeping services ; schedule jobs and configure devices

    ; manage memory

    ; manage programs

    ; provide user interface

    Where is the operating system located?

    ; operating system resides on ROM in handhelds ; operating system resides on hard disk in most cases What is a cross-platform application?

    ; One that runs identically on multiple operating systems

    o Windows 95, 98, 2000, ME, and XP

    Operating System Functions

    What is booting?

    ; Process of starting or restarting a computer ; Cold boot

    o Process of turning on a computer after it has been powered off completely

    ; Warm boot

    o Process of restarting a computer that is already powered on

    What messages display on the screen when you boot the computer?

    ; BIOS version and copyright notice

    ; Total amount of memory

    ; Devices detected and tested

    ; Windows message

    ; Sound card and CD-ROM drivers loaded

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