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Section A. Data, Information, and Files. CHAPTER 4. Computer Files and Data Storage. Page 158. Section A. Data, Information, and Files. Chapter 4. Section PREVIEW. Section D. Section A. You will be able to:. Correctly use the terms “data” and “information”

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Computer files and data storage

Section A

Data, Information, and Files

CHAPTER

4

Computer Files and Data Storage

Page 158


Section A

Data, Information, and Files

Chapter

4

SectionPREVIEW

Section D

Section A

You will be able to:

  • Correctly use the terms “data” and “information”

  • Create valid file names under DOS and Windows

  • Explain how wildcards and file extensions simplify file access

  • Determine if a file is an executable file or a data file

Page 158


Data and Information: Technically Speaking

Aren’t data and information the same thing?

Chapter

4

Section A

  • Data is words, numbers, and graphics that describe people, events, things, and ideas.

    • used by computers

  • Information is the words, numbers, and graphics used as the basis for human actions and decisions.

    • used by humans

Page 160


Computer Files

What kinds of files are stored on a computer?

Chapter

4

Section A

  • File - named collection of data that exists on a storage medium such as a hard disk or floppy drive

Page 160


File Naming Conventions

May I use any name I want when I create my own files?

Chapter

4

Section A

  • Filename

    • unique set of letter and numbers

    • identifies a file

    • describes the file contents

  • Filenameextension further describes the file contents.

    • separated by the filename with a dot

  • You must provide a valid filename that adheres to rules or filenamingconventions.

Page 161


Wildcards

Is * * a filename?

Chapter

4

Section A

  • The asterisk is a wildcard character used to represent a group of characters in the filename or extension.

  • Wildcards are handy for finding specific files on a hard disk.

Page 162


File Extensions and File Types

Why do I need to know about file extensions?

Chapter

4

Section A

You can access files efficiently if you are familiar with the characteristics of file categories.

Page 163


Executable Files

How do I use executable files?

Chapter

4

Section A

  • An executable file contains the program instructions that tell a computer how to perform a specific task.

  • Most have .exe or .com extensions.

Executable

files have

.exe file

extensions

Page 163


Data Files

How do I use data files?

Chapter

4

Section A

  • A data file contains words, numbers, and pictures that you can view, edit, save, send, and print.

    • Passive, unlike executable files which are active

    • created using application software

    • receive data files on CD-ROMS such as clip art

  • You manipulate a data file using the same software that was used to create it.

Page 164


Data Files

How do I use data files?

Chapter

4

Section A

Section A

  • The standard method for opening a data file is to start an application, then use the open command.

  • A generic filename extension indicates general type of data contained in a file.

    • a .bmp could be opened in Microsoft Paint or MicroGrafx Picture Publisher

Page 165


Data Files

How do I use data files?

Chapter

4

Section A

  • An application-specificfilenameextension is associated with a particular application

Application-

specific

filename

extensions

Page 166


Configuration Files, and Program Modules

What other kinds of files will I find on my computer?

Chapter

4

Section A

  • Other files are necessary for hardware and software operations and should not be deleted.

Page 167


Computer files and data storage1

Section B

File Manager Utility Software

CHAPTER

4

Computer Files and Data Storage

PARSONS/OJA

Page 168


Section B

File Manager Utility Software

Chapter

4

SectionPREVIEW

Section D

Section B

You will be able to:

  • Describe the difference between logical and physical file storage

Page 168


Section B

Worksheets

File Manager Utility Software

Chapter

4

Section B

  • File manager utility software

    • provided by your computer operating system

    • helps you locate, rename, move, copy and delete files

Page 168


Device Letters

Why do storage devices have letters?

Chapter

4

Section B

  • A storage device, such as a floppy disk drive, a hard drive, and a CD-ROM drive, is identified by a letter called a device letter.

    • floppy disk drive = A

    • main hard disk = C

    • additional storage devices = D through Z

Page 168


Directories and Folders

How can I get a list of files that are stored on a disk?

Chapter

4

Section B

Section B

  • An operating system maintains a list of files called a directory for each disk, CD-ROM or DVD.

  • Directory includes

    • filename

    • filename extension

    • date and time file was created

    • file size

Page 169


Directories and Folders

How can I get a list of files that are stored on a disk?

Chapter

4

Section B

Section B

Operating

system’s

file manager

utility displays

lots of information

about the files

stored on a

computer

Page 169


Directories and Folders

How can I get a list of files that are stored on a disk?

Chapter

4

Section B

Section B

  • Root directory

    • main directory of a disk

    • provides a useful list of files

  • Folders - smaller lists within directories

  • A folder is separated from a drive letter and a filename by a backslash (\).

Page 169


Directories and Folders

How can I get a list of files that are stored on a disk?

Chapter

4

Section B

Section B

A file specification (path) is the drive letter, folder, filename, and extension that identifies a file.

A:\Word\Gumbo.doc

drive letter

extension

filename

subdirectory (folder)

Page 170


Storage Models

How does file manager utility software depict files and folders?

Chapter

4

Section B

  • File manager utility software provides a metaphorical view of the files stored on a computer.

    • also called logical models

      • filing cabinet

      • tree structure

Page 170


Storage Models

How does file manager utility software depict files and folders?

Chapter

4

Section B

A file cabinet

metaphor depicts a

storage device as a

drawer of a filing

cabinet containing

folders and documents.

Page 170


Storage Models

How does file manager utility software depict files and folders?

Chapter

4

Section B

  • Visualize a disk directory as a tree.

    • trunk and branches are folders

    • leaves are files

You can visualize

the directory

of a disk as a

tree on its side.

Page 171


Storage Models

How does file manager utility software depict files and folders?

Chapter

4

Section B

Windows

Explorer

Page 172


Using File Manager Utility Software

How do I use file manager utility software?

Chapter

4

Section B

  • Find - to locate a file

  • Rename - to change the name

  • Copy - to copy a file

  • Move - to move file from one folder to another

  • Delete - when you no longer need a file

Page 172


Computer files and data storage2

Section C

How Computers Store File Data

CHAPTER

4

Computer Files and Data Storage

Page 174


Section C

How Computers Store File Data

Chapter

4

SectionPREVIEW

Section D

Section C

You will be able to:

  • Describe the difference between logical and physical file storage

  • Discuss how the directory and the FAT help you access files

Page 174


Section C

How Computers Store File Data

Chapter

4

Section C

  • The data for a single file can be scattered all over the surface of a disk.

  • Physical storage - way computer store data on a disk.

  • Logical storage - conceptual model of files and folders.

Page 174


Storage Terminology

What are the basic components of a data storage system?

Chapter

4

Section C

  • Storagemedium - the disk, tape, CD, DVD, paper, or other substance that contains data

  • Storagedevice - mechanical apparatus that records and retrieves data from a storage medium

    • floppy disk drives

    • hard disk drives

    • CD drives

    • DVD drives

    • tape drives

Page 174


Storage Terminology

What are the basic components of a data storage system?

Chapter

4

Section C

  • Storagetechnology - a storage device and the media it uses.

  • Storing - also known as

    • writing data (mainframe applications)

    • saving a file (Windows terminology)

  • Retrieving - also known as

    • reading data (mainframe applications)

    • loading data

    • opening a file (Windows terminology)

Page 174


Bits and Bytes

If I enter a letter or number how is it actually stored?

Chapter

4

Section C

  • Computers use codes to convert information into digital data.

    • series of 1s and 0s

  • Bit - smallest unit for digitizing data

  • Byte - 8 bits

  • A byte represents:

    • a character

    • a space

    • numeral

    • punctuation

Page 174


Magnetic and Optical Technologies

How does a computer get the 1s and 0s onto the storage medium?

Chapter

4

Section C

  • 1s and 0s are changed in the surface of the storage medium.

  • Transformation depends on storage technology.

  • Magneticstorage - stores data by magnetizing microscopic particles on the disk or tape surface

  • Read-writehead - mechanism in the disk drive that reads and writes magnetized particles that represent data

Page 175


Magnetic and Optical Technologies

How does a computer get the 1s and 0s onto the storage medium?

Chapter

4

Section C

Disk surface

Read-write head

Storing data

on

magnetic

media

Mylar disk

Page 175


Magnetic and Optical Technologies

How does a computer get the 1s and 0s onto the storage medium?

Chapter

4

Section C

  • Data stored on magnetic media such as floppy disks can be altered by dust, smoke, heat, and mechanical problems.

  • Some experts estimate that the reliable life span of data stored on magnetic media is about three years.

Page 175


Magnetic and Optical Technologies

How does a computer get the 1s and 0s onto the storage medium?

Chapter

4

Section C

  • Optical storage stores data as microscopic light spots (lands) and dark spots (pits) on the disk surface.

  • Data stored on an optical storage device is less susceptible to environmental damage.

Page 176


Magnetic and Optical Technologies

How does a computer get the 1s and 0s onto the storage medium?

Chapter

4

Section C

Optical

storage devices

read data

using reflected

laser light

Page 176


Tracks, Sectors, and Clusters

Is data stored in specific places on a disk, tape, or CD?

Chapter

4

Section C

  • Tracks - electronic storage bins

    • parallel to the edge of the tape

    • spiral out from the center of the disk

    • arranged as concentric circles or

  • Tracks that are arranged in concentric circles are divided into wedge-shaped sectors

  • Cluster - a group of sectors

Page 177


Tracks, Sectors, and Clusters

Is data stored in specific places on a disk, tape, or CD?

Chapter

4

Section C

A formatted

disk is

divided into

circular

tracks

Page 177


File Allocation Tables

How does a computer keep track of the location of every file?

Chapter

4

Section C

  • File allocation table (FAT) - an operating system file that maintains a list of files and their physical location on the disk.

    • like a table of contents

    • a damaged FAT results in losing data

  • Back up data on hard disk.

Page 177


File Allocation Tables

How does a computer keep track of the location of every file?

Chapter

4

Section C

  • Computer looks for empty clusters to store data

  • Name of new file and number of cluster are recorded in the FAT

  • Files that do not fit in one cluster spill over to contiguous or noncontiguous clusters, depending on availability.

  • Pointers - instructions that point to each piece of the file

Page 178


File Allocation Tables

How does a computer keep track of the location of every file?

Chapter

4

Section C

Section C

Each colored

cluster

represents

part of a file

Page 178


File Allocation Tables

How does a computer keep track of the location of every file?

Chapter

4

Section C

  • It takes longer to retrieve a file stored in noncontiguous clusters.

  • When you delete a file, the clusters’ status becomes “empty” but retains old data until new data is stored.

  • You may be able to retrieve data using an undelete utility.

    • Recycle Bin’s Restore feature

Page 179


File Allocation Tables

How does a computer keep track of the location of every file?

Chapter

4

Section C

  • Files stored in many noncontiguous clusters become fragmented.

    • drive performance declines

    • becomes harder to locate clusters

  • A defragmentationutilityrearranges files in contiguous clusters

    • improves drive performance

Page 179


Computer files and data storage3

Section D

Disks, Tapes, CDs, and DVDs

CHAPTER

4

Computer Files and Data Storage

Page 180


Section D

Disks, Tapes, CDs, and DVDs

Chapter

4

SectionPREVIEW

Section D

Section D

You will be able to:

  • Select a storage device based on characteristics such as its capacity and access speed

Page 180


Section D

Disks, Tapes, CDs, and DVDs

Chapter

4

Section D

There are many types of storage devices, each with unique advantages and disadvantages.

Page 180


Section D

Disks, Tapes, CDs, and DVDs

Chapter

4

Section D

  • Versatility

    • can access data from different media

  • Durability

    • less susceptible to damage

  • Storage capacity - maximum amount of data that can be stored on a storage medium

    • kilobyte = approximately 1000 bytes

    • megabyte = approximately 1 million bytes

    • gigabyte = approximately 1 billion bytes

    • terabyte = approximately 1 trillion bytes

Page 180


Section D

Disks, Tapes, CDs, and DVDs

Chapter

4

Section D

  • Speed -measured by access time and data transfer rate

  • Access time - average time it takes a computer to locate data and read it

    • millisecond = one-thousandth of a second

  • Randomaccess- ability of a device to jump directly to the track or sector holding the data

    • floppy disk, hard drive, CD, DVD

Page 180


Section D

Disks, Tapes, CDs, and DVDs

Chapter

4

Section D

  • Sequentialaccess - reads through from beginning of tape

    • tape drive

  • Data transfer rate - amount of data that moves per second

Page 180


Floppy Disk Storage

Why is it called a floppy disk?

Chapter

4

Section D

  • Floppydisk - round piece of flexible mylar plastic covered with thin layer of magnetic oxide.

    • sealed in protective casing

    • also called floppies or diskettes

    • inside casing is “floppy”

    • not as speedy as zips

    • decreased use

  • Zipdisk - high-capacity floppy disk manufactured by Iomega Corporation.

Page 181


Floppy Disk Storage

Why is it called a floppy disk?

Chapter

4

Section D

  • Double-sideddisk - stores twice as much as single-sided

  • Diskdensity - closeness and size of magnetic particles it stores

  • High-densitydisk - stores more data than double-density

Page 182


Floppy Disk Storage

Why is it called a floppy disk?

Chapter

4

Section D

Disk

capacities

Page 182


Hard Disk Storage

How can a hard disk be the same size as a floppy, but store so much more data?

Chapter

4

Section D

  • Hard disk platter - a flat, rigid disk made of aluminum or glass and coated with magnetic oxide

    • density far exceeds floppy disk

  • Harddisk - one or more platters and their associated read-write heads.

    • preferred type of main storage

  • Cylinder

    • vertical set of tracks

    • basic storage bin for hard disk drive

Page 183


Hard Disk Storage

How can a hard disk be the same size as a floppy, but store so much more data?

Chapter

4

Section D

Hard disk

platters prevent

dust from

interfering with

read-write

heads

Page 183


Hard Disk Storage

How can a hard disk be the same size as a floppy, but store so much more data?

Chapter

4

Section D

  • Hard disks

    • provide random access to files

    • faster than floppy disk access

    • continually in motion

Page 184


Hard Disk Storage

How can a hard disk be the same size as a floppy, but store so much more data?

Chapter

4

Section D

  • Headcrash - when a read-write head runs into a dust particle or other contaminant on the disk.

    • head crash damages some data on disk

    • triggered by jarring the hard disk while in use

  • Removableharddisk - hard disks that can be inserted and removed from drive

    • increase storage capacity

    • provides security for data

Page 185


Hard Disk Storage

How can a hard disk be the same size as a floppy, but store so much more data?

Chapter

4

Section D

  • RAID - (redundant array of independent disks)

    • type of hard disk storage

    • found on mainframe and microcomputer installations

    • contains many disk platters

    • provides redundancy

    • faster data access

Page 185


Hard Disk Storage

How can a hard disk be the same size as a floppy, but store so much more data?

Chapter

4

Section D

  • Disk cache

    • special area of computer memory

    • computer transfers data you are likely to need

    • reads data from nearby sectors and stores it in the cache

Page 185


Tape Storage

Do they still use those big tape drives on computers that you see in old movies?

Chapter

4

Section D

  • Tape

    • most popular form of storage in 1960s

    • continued in form of cassette tape drive

    • requires sequential access

    • inconvenient and slow

  • Recent revival in tape storage for backing up data, not for principal storage device.

  • Tapebackup - copy of data on hard disk stored on magnetic tape.

Page 186


Tape Storage

Do they still use those big tape drives on computers that you see in old movies?

Chapter

4

Section D

  • Open reel tapes

    • large reels seen in old movies

    • access speeds measured in seconds

    • still used as distribution medium for some mainframe and minicomputer systems

  • Tape cartridge - a removable magnetic tape module similar to a cassette tape.

Page 187


CD-ROM Technology

If CD-ROMS are read only, doesn’t that limit their use?

Chapter

4

Section D

  • CD-ROM

    • stands for Compact Disc Read-Only Memory

    • data stamped on when manufactured

    • holds up to 680 MB

    • coated with clear plastic, durable

    • estimated life exceeds 500 years

    • inexpensive to manufacture

    • ideal for distribution of large files

Page 188


CD-ROM Technology

If CD-ROMS are read only, doesn’t that limit their use?

Chapter

4

Section D

  • CD-ROMS

    • choice for delivery of multimedia applications

    • read-only storage memory

  • Read-only - computer can retrieve from it but not save new data on it

  • CD-ROM drives

    • standard on today’s computers

    • speeds up to 40X

Page 188


CD-R Technology

Can I make my own CD-ROMs?

Chapter

4

Section D

  • CD-R

    • stands for compact disc-recordable

    • allows you to create your own CDs by recording on a CD-R disk

  • Recording is done on a CD-R drive

    • uses a laser to change the reflectivity of a dye layer on a blank CD-R disk.

Page 189


CD-R Technology

Can I make my own CD-ROMs?

Chapter

4

Section D

  • Disks produced on CD-R drive

    • can be used on CD-ROM and DVD drives

    • cannot be erased or modified

    • some drives have multisessionsupport (can record in multiple sessions)

      • available after 1998

  • Archiving - moving data that is not accessed frequently off of a primary storage device

Page 189


CD-RW Technology

Is there any way to change the data on a CD?

Chapter

4

Section D

  • CD-RW (compact disc-rewritable) allows you to write on a CD, then change the data

    • requires special CD-RW disks

    • requires special CD-RW drive

    • requires phase change technology

  • Phase change technology - alters the crystal structure on the disk surface

Page 189


DVD Technology

How is DVD different from CD technology?

Chapter

4

Section D

  • DVD (digital video disc or digital versatile disc)

    • variation of CD technology

    • designed to provide enough storage capacity for a full length movie

    • will replace video tape (experts believe)

  • DVD-ROM disk

    • stamped with data when manufactured

    • cannot change or add data

    • stores 4.7 GB

    • ideal for games, maps, large databases

Page 190


DVD+RW and DVD-RAM Technology

Is there a DVD equivalent to CD-RW?

Chapter

4

Section D

  • DVD+RW

    • uses phase change technology

    • cannot be used on DVD-RAM

  • DVD-RAM

    • uses a blend of technologies to record data

    • cannot be used on DVD+RW

  • Both DVD+RW and DVD-RAM can be read on DVD-ROM drives.

Page 190


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