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Computer Concepts 4th EditionParsons/Oja
CHAPTER
4
Page 158
Data, Information, and FilesSection A
Computer Files and Data Storage
Computer Concepts 4th EditionParsons/Oja
Section D
Chapter
4Section A
Page 158
Section A
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
Section PREVIEW
You will be able to:
Data, Information, and Files
Computer Concepts 4th EditionParsons/Oja
Data and Information: Technically Speaking
Aren’t data and information the same thing?
Chapter
4
Page 160
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
Computer Concepts 4th EditionParsons/Oja
Computer Files
What kinds of files are stored on a computer?
Chapter
4
Page 160
Section A
File - named collection of data that exists on a storage medium such as a hard disk or floppy drive
Computer Concepts 4th EditionParsons/Oja
File Naming Conventions
May I use any name I want when I create my own files?
Chapter
4
Page 161
Section A
Filename– unique set of letter and numbers– identifies a file– describes the file contents
Filename extension further describes the file contents.– separated by the filename with a dot
You must provide a valid filename that adheres to rules or file naming conventions.
Computer Concepts 4th EditionParsons/Oja
Page 162
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.
Wildcards
Is * * a filename?
Chapter
4
Section A
Computer Concepts 4th EditionParsons/Oja
Page 163
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.
Computer Concepts 4th EditionParsons/Oja
Page 163
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
How do I use executable files?
Chapter
4
Section A
Executablefiles have .exe fileextensions
Computer Concepts 4th EditionParsons/Oja
Data Files
How do I use data files?
Chapter
4
Page 164
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.
Computer Concepts 4th EditionParsons/Oja
Page 165
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
Section A
Data Files
How do I use data files?
Chapter
4
Section A
Computer Concepts 4th EditionParsons/Oja
Page 166
An application-specific filename extension is associated with a particular application
Data Files
How do I use data files?
Chapter
4
Section A
Application-specificfilenameextensions
Computer Concepts 4th EditionParsons/Oja
Page 167
Other files are necessary for hardware and software operations and should not be deleted.
Configuration Files, and Program Modules
What other kinds of files will I find on my computer?
Chapter
4
Section A
F I G U R E 4 - 8
F i l e n a m e E x t e n s i o n s f o r C o n f i g u r a t i o n F i l e s
a n d P r o g r a m M o d u l e s
T yp e o f F i l e D e s c r i p t i o n F i l e n a m e
E x t e n s i o n
B a t c h f i l e A s e q u e n c e o f o p e r a t i n g s y s t e m c o m m a n d s t h a t a r e
e x e c u t e d a u t o m a t i c a l l y w h e n t h e c o m p u t e r b o o t s .
. b a t
C o n f i g u r a t i o n f i l e I n f o r m a t i o n a b o u t p r o g r a m s t h a t t h e c o m p u t e r u s e s
t o a l l o c a t e t h e r e s o u r c e s n e c e s s a r y t o r u n t h e m .
. c f g , . s y s ,
. m i f , . i n i
H e l p T h e i n f o r m a t i o n t h a t i s d i s p l a y e d b y o n l i n e H e l p . . h l p
T e m p o r a r y f i l e A s o r t o f “ s c r a t c h p a d ” t h a t c o n t a i n s d a t a w h i l e a
p r o g r a m i s r u n n i n g , b u t t h a t i s d i s c a r d e d w h e n
y o u e x i t t h e p r o g r a m .
. t m p
P r o g r a m s u p p o r t
m o d u l e s
P r o g r a m i n s t r u c t i o n s t h a t a r e e x e c u t e d i n
c o n j u n c t i o n w i t h t h e m a i n . e x e f i l e f o r a p r o g r a m .
. o c x , . v b x ,
. d l l
Computer Concepts 4th EditionParsons/Oja
CHAPTER
4 PARSONS/OJA
Page 168
File Manager Utility SoftwareSection B
Computer Files and Data Storage
Computer Concepts 4th EditionParsons/Oja
Section D
Chapter
4
Page 168
Section B
Describe the difference between logical and physical file storage
Section PREVIEW
You will be able to:
File Manager Utility SoftwareSection B
Computer Concepts 4th EditionParsons/Oja
Chapter
4
Page 168
Section B
File manager utility software – provided by your computer operating
system– helps you locate, rename, move, copy and
delete files
WorksheetsFile Manager Utility SoftwareSection B
Computer Concepts 4th EditionParsons/Oja
Device Letters
Why do storage devices have letters?
Chapter
4
Page 168
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
Computer Concepts 4th EditionParsons/Oja
Page 169
Section B
Directories and Folders
How can I get a list of files that are stored on a disk?
Chapter
4
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
Computer Concepts 4th EditionParsons/Oja
Page 169
Section B
Directories and Folders
How can I get a list of files that are stored on a disk?
Chapter
4
Section B
Operatingsystem’s file managerutility displayslots of informationabout the filesstored on acomputer
Computer Concepts 4th EditionParsons/Oja
Page 169
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 (\).
Section B
Directories and Folders
How can I get a list of files that are stored on a disk?
Chapter
4
Section B
Computer Concepts 4th EditionParsons/Oja
Page 170
Section B
A file specification (path) is the drive letter, folder, filename, and extension that identifies a file.
A:\Word\Gumbo.doc
Chapter
4
Section B
Directories and Folders
How can I get a list of files that are stored on a disk?
drive letter
subdirectory (folder)
filename extension
Computer Concepts 4th EditionParsons/Oja
Page 170
Section B
Storage Models
How does file manager utility software depict files and folders?
Chapter
4
File manager utility software provides a metaphorical view of the files stored on a computer.– also called logical models
• filing cabinet• tree structure
Computer Concepts 4th EditionParsons/Oja
Page 170
Section B
Storage Models
How does file manager utility software depict files and folders?
Chapter
4
A file cabinet metaphor depicts astorage device as adrawer of a filingcabinet containingfolders and documents.
Computer Concepts 4th EditionParsons/Oja
Page 171
Section B
Storage Models
How does file manager utility software depict files and folders?
Chapter
4
You can visualizethe directoryof a disk as a tree on its side.
Visualize a disk directory as a tree.– trunk and branches
are folders– leaves are files
Computer Concepts 4th EditionParsons/Oja
Page 172
Section B
Storage Models
How does file manager utility software depict files and folders?
Chapter
4
WindowsExplorer
Computer Concepts 4th EditionParsons/Oja
Page 172
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
Section B
Using File Manager Utility Software
How do I use file manager utility software?
Chapter
4
Computer Concepts 4th EditionParsons/Oja
CHAPTER
4
Page 174
How Computers Store File DataSection C
Computer Files and Data Storage
Computer Concepts 4th EditionParsons/Oja
Section D
Chapter
4
Page 174
Section C
Describe the difference between logical and physical file storage
Discuss how the directory and the FAT help you access files
Section PREVIEW
You will be able to:
How Computers Store File DataSection C
Computer Concepts 4th EditionParsons/Oja
Chapter
4
Page 174
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.
How Computers Store File DataSection C
Computer Concepts 4th EditionParsons/Oja
Storage Terminology
What are the basic components of a data storage system?
Chapter
4
Page 174
Section C
Storage medium - the disk, tape, CD, DVD, paper, or other substance that contains data
Storage device - mechanical apparatus that records and retrieves data from a storage medium– floppy disk drives– hard disk drives– CD drives– DVD drives– tape drives
Computer Concepts 4th EditionParsons/Oja
Page 174
Storage technology - 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)
Storage Terminology
What are the basic components of a data storage system?
Chapter
4
Section C
Computer Concepts 4th EditionParsons/Oja
Bits and Bytes
If I enter a letter or number how is it actually stored?
Chapter
4
Page 174
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
Computer Concepts 4th EditionParsons/Oja
Magnetic and Optical Technologies
How does a computer get the 1s and 0s onto the storage medium?
Chapter
4
Page 175
Section C
1s and 0s are changed in the surface of the storage medium.
Transformation depends on storage technology. Magnetic storage - stores data by magnetizing
microscopic particles on the disk or tape surface Read-write head - mechanism in the disk drive
that reads and writes magnetized particles that represent data
Computer Concepts 4th EditionParsons/Oja
Page 175
Magnetic and Optical Technologies
How does a computer get the 1s and 0s onto the storage medium?
Chapter
4
Section C
Storing dataon magneticmedia
Read-write head
Disk surface
Mylar disk
Computer Concepts 4th EditionParsons/Oja
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.
Computer Concepts 4th EditionParsons/Oja
Page 176
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.
Magnetic and Optical Technologies
How does a computer get the 1s and 0s onto the storage medium?
Chapter
4
Section C
Computer Concepts 4th EditionParsons/Oja
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 devicesread data using reflectedlaser light
Computer Concepts 4th EditionParsons/Oja
Tracks, Sectors, and Clusters
Is data stored in specific places on a disk, tape, or CD?
Chapter
4
Page 177
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
Computer Concepts 4th EditionParsons/Oja
Tracks, Sectors, and Clusters
Is data stored in specific places on a disk, tape, or CD?
Chapter
4
Page 177
Section C
A formatteddisk is divided intocircular tracks
Computer Concepts 4th EditionParsons/Oja
File Allocation Tables
How does a computer keep track of the location of every file?
Chapter
4
Page 177
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.
Computer Concepts 4th EditionParsons/Oja
Page 178
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
File Allocation Tables
How does a computer keep track of the location of every file?
Chapter
4
Section C
Computer Concepts 4th EditionParsons/Oja
Page 178
Section C
File Allocation Tables
How does a computer keep track of the location of every file?
Chapter
4
Section C
Each coloredclusterrepresentspart of a file
Computer Concepts 4th EditionParsons/Oja
Page 179
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
File Allocation Tables
How does a computer keep track of the location of every file?
Chapter
4
Section C
Computer Concepts 4th EditionParsons/Oja
Page 179
Files stored in many noncontiguous clusters become fragmented.– drive performance declines– becomes harder to locate clusters
A defragmentation utility rearranges files in contiguous clusters– improves drive performance
File Allocation Tables
How does a computer keep track of the location of every file?
Chapter
4
Section C
Computer Concepts 4th EditionParsons/Oja
CHAPTER
4
Page 180
Disks, Tapes, CDs, and DVDsSection D
Computer Files and Data Storage
Computer Concepts 4th EditionParsons/Oja
Section D
Chapter
4
Page 180
Section D
Select a storage device based on characteristics such as its capacity and access speed
Section PREVIEW
You will be able to:
Disks, Tapes, CDs, and DVDsSection D
Computer Concepts 4th EditionParsons/Oja
Chapter
4
Page 180
Section D
There are many types of storage devices, each with unique advantages and disadvantages.
Disks, Tapes, CDs, and DVDsSection D
Computer Concepts 4th EditionParsons/Oja
Page 180
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
Chapter
4
Section D
Disks, Tapes, CDs, and DVDsSection D
Computer Concepts 4th EditionParsons/Oja
Page 180
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
Random access - ability of a device to jump directly to the track or sector holding the data– floppy disk, hard drive, CD, DVD
Chapter
4Disks, Tapes, CDs, and DVDsSection D
Section D
Computer Concepts 4th EditionParsons/Oja
Page 180
Sequential access - reads through from beginning of tape– tape drive
Data transfer rate - amount of data that moves per second
Chapter
4Disks, Tapes, CDs, and DVDsSection D
Section D
Computer Concepts 4th EditionParsons/Oja
Floppy Disk Storage
Why is it called a floppy disk?
Chapter
4
Page 181
Section D
Floppy disk - 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
Zip disk - high-capacity floppy disk manufactured by Iomega Corporation.
Computer Concepts 4th EditionParsons/Oja
Page 182
Floppy Disk Storage
Why is it called a floppy disk?
Chapter
4
Section D
Double-sided disk - stores twice as much as single-sided
Disk density - closeness and size of magnetic particles it stores
High-density disk - stores more data than double-density
Computer Concepts 4th EditionParsons/Oja
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Floppy Disk Storage
Why is it called a floppy disk?
Chapter
4
Section D
Disk capacities
Computer Concepts 4th EditionParsons/Oja
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Hard disk platter - a flat, rigid disk made of aluminum or glass and coated with magnetic oxide– density far exceeds floppy disk
Hard disk - 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
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
Computer Concepts 4th EditionParsons/Oja
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 diskplatters preventdust from interfering withread-writeheads
Computer Concepts 4th EditionParsons/Oja
Page 184
Hard disks– provide random access to files– faster than floppy disk access– continually in motion
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
Computer Concepts 4th EditionParsons/Oja
Page 185
Head crash - 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 Removable hard disk - hard disks that can
be inserted and removed from drive– increase storage capacity– provides security for data
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
Computer Concepts 4th EditionParsons/Oja
Page 185
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
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
Computer Concepts 4th EditionParsons/Oja
Page 185
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
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
Computer Concepts 4th EditionParsons/Oja
Page 186
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.
Tape backup - copy of data on hard disk stored on magnetic tape.
Tape Storage
Do they still use those big tape drives on computers that you see in old movies?
Chapter
4
Section D
Computer Concepts 4th EditionParsons/Oja
Page 187
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.
Tape Storage
Do they still use those big tape drives on computers that you see in old movies?
Chapter
4
Section D
Computer Concepts 4th EditionParsons/Oja
Page 188
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
CD-ROM Technology
If CD-ROMS are read only, doesn’t that limit their use?
Chapter
4
Section D
Computer Concepts 4th EditionParsons/Oja
Page 188
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
CD-ROM Technology
If CD-ROMS are read only, doesn’t that limit their use?
Chapter
4
Section D
Computer Concepts 4th EditionParsons/Oja
Page 189
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.
CD-R Technology
Can I make my own CD-ROMs?
Chapter
4
Section D
Computer Concepts 4th EditionParsons/Oja
Page 189
Disks produced on CD-R drive – can be used on CD-ROM and DVD drives– cannot be erased or modified– some drives have multisession support
(can record in multiple sessions)• available after 1998
Archiving - moving data that is not accessed frequently off of a primary storage device
CD-R Technology
Can I make my own CD-ROMs?
Chapter
4
Section D
Computer Concepts 4th EditionParsons/Oja
Page 189
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
CD-RW Technology
Is there any way to change the data on a CD?
Chapter
4
Section D
Computer Concepts 4th EditionParsons/Oja
Page 190
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
DVD Technology
How is DVD different from CD technology?
Chapter
4
Section D
Computer Concepts 4th EditionParsons/Oja
Page 190
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.
DVD+RW and DVD-RAM Technology
Is there a DVD equivalent to CD-RW?
Chapter
4
Section D
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