1 computer concepts isys 1050a mrs. karla steere
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Computer Concepts
ISYS 1050A
Mrs. Karla Steere
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Computer
Literacy
Proficiency
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Purposes of Computers
Business purposes/uses
Personal purposes/uses
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Types of Computers
Personal Computers
Personal Digital Assistants
Workstations
Mainframes
Supercomputers
Servers
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Types of Computers
Personal Computers
Desktop & laptop/notebook
Personal and business use;
animation, sound recording
Personal Digital Assistants
(PDA)
Personal, on-the-go tasks;
appointment calendars
Small, very portable, connect
to PC’s to exchange info.
Handheld
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Workstations
Engineers: model airplane
fuselages
Create digital video and animation
Expensive Powerful desktop
computers
Specialized tasks
Mainframes
Banks
Airlines
Insurance companies
Universities
More powerful
Mid- to large-size capacity
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Supercomputers
Weather forecasting
Oil exploration
Aircraft design
Scientific computations
Fastest
Highest-capacity
Thousands of processors
Very expensive
ServersA computer in a
network
Provides services (access to files,
shared peripherals)
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Information Systems
Hardware
Software
Data/information
Procedures
People
Communications/Connectivity
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What Is a Computer?
A device made up of:ElectronicElectromechanicalMechanical
Referred to as “hardware”
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Software
Instructions
Programs
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Data/Information
Data Raw facts and figures
Information Processed data
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Procedures
Documentation
On-line Manuals
Common Methods
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Communications and Connectivity
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Peripheral Devices
External devices connected to the computer, but not inside the main cabinet/unit
Examples: keyboard, mouse, monitor, printer
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Hardware Categories
Input
Processing and Memory
Storage
Output
Communications
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Input Devices
Accept data
Convert data to form that can be processed
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Types of Input Devices
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Processing Hardware
Microprocessor - CPUControl Unit – interprets instructionsArithmetic/Logic Unit – processesMeasured in Megahertz or MIPS
Coprocessors – math or graphics
ROM BIOS – firmware
Machine Language
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Processors
1.5” – square chip attached to
motherboard
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Motherboard
Aka: system board
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Memory
Memory (RAM) – data & InstructionsKilobytes or MegabytesPower off – contents are gone
More memory means you can open more programs
Registers – instructions & data are loaded here just before processing
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Memory
Memory (RAM) – data & Instructions Kilobytes or Megabytes Power off – contents are gone
More memory means you can open more programsRegisters – instructions & data are loaded here just before processingMost common memory—found in printers and other devices
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Cache
High-speed memory
Keeps information about instructions used over and over again here for fast access
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Clock Speed
Timing device that controls pace.
Hertz
Megahertz (MHz)
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Memory
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Memory and Storage Capacity
Approximate values:b or Bit – 1 binary digitB or Byte – 8 bitsKB or Kilobyte – 1 thousand bytesMB or Megabyte – 1 million bytesGB or Gigabyte – 1 billion bytesTB or Terabyte – 1 trillion bytes
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Storage Hardware
3.5" Floppy Disk Drive
Iomega Zip and Jaz Drives
CD-R and CD-RW
DVD-R and DVD-RW
Hard Disk Drive
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Storage Devices
1.44 MB 100 or 250 MB CD-680 MB
Up to 100 GB1-2 GB
DVD-4 to 17 GB
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3½" Floppy Disks
High Density1.44 MB
Data is recorded in sectors
Formatting – readies disk for use
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Hard Drives
December
2001
40 GB $79
60 GB $149 -$179
80 GB $199
August 2002
80 GB $169
120 GB $149
160 GB $179
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Iomega Zip Drives
100 or 250 MB
$70 – $135 Internal or External USB
Disks $8 - $15
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Iomega Jaz Drive
1 or 2 GB
$90+ Internal or External USB
$99 (One 1GB Disk)
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Compact Discs – Optical Discs
CD-ROM (compact disk ROM)CD-R (compact disk-recordable)CD-RW (compact disk-rewritable)
DVD-ROM (digital video disc-ROM)DVD-R (digital video disk-recordable)DVD-RW (digital video disk-rewritable)
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Compact Disks
680 MB
Speeds (e.g., 40X)
CD-ROM CD-R CD-RW
Retrieve data X X X
Write (save) X X
Modify & save X
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Digital Video Disks
4.7 – 17 GB
Speeds (e.g., 16X)
Movies and Multimedia Presentations
DVD-ROM DVD-R DVD-RW
Retrieve data X X X
Write (save) X X
Modify and save X
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Compact Disk Speeds
SpeedTransfer Speed
Per Second
4x 600 K (4 x 150KB)
12x 1.8 MB
24x 3.6 MB
40x 6 MB
Transfer Speed is the speed at which data is transferred from the CD into
memory.
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Data Disk Rules
Keep away from extreme temperatures.
Keep disks and CDs in storage cases.
Keep disks away from magnetic forces.
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Read and Write
Read Copies data from storage medium to RAM.
Write Copies data from main memory to storage medium.
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Tracks and Sectors
TracksElectronic storage binsClosed concentric ringsDivided into sectors
SectorsTrack subdivisionWedge-shaped
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File Allocation Table (FAT)
Files are saved in clusters.
FAT maintains list of files and physical locations.
You should backup files regularly in case FAT damaged!
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Fragmented Disk
Files stored in noncontiguous clusters
Slow access
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Defragmented Disk
Clusters for files moved to contiguous clusters
Data access: more efficient
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Formatting
Prepares disk to be able to store data.
Makes sure sectors are reliable.
Marks bad sectors to avoid trying to save there
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Output Devices
Return processed data in form of information
View and use information
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Soft & Hard Copy
Soft Copy—temporary displayMonitor
Hard Copy—more permanent displayPrinted copy
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Types of Output Devices
Monitor
Printer
Speakers
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Monitor Types
CRT Monitors Similar to TV
technology Heavy and bulky
LCD Monitors Flat monitors Difficult to view from
angles
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Monitor Sizes
Physical Size15" small17" medium19" & 21" large
Viewable Size (Area)Actual area you see
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Monitor Clarity
Resolution (pixels per square inch)640 x 480800 x 6001280 x 1024
Dot Pitch (spacebetween pixels)
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Types of Printers
Laser
Inkjet
Dot Matrix
Requires a driver
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Laser Printers
Prints series of dots created on a drum (like a copy machine).
Transfers drum image to paper.
Prints 12-25 ppm.
Produces highest-quality printouts.
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Inkjet Printer
Sprays ink on page.
Costs less than laser printers.
Prints up to 15 ppm (depending on b&w or color, # of images, etc.)
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Dot Matrix Printers
Prints by striking mechanism against ribbon, similar to typewriter.
Produces up to 337 cps (slow).
Produces lower resolution than laser or ink-jet.
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Audio Output
Voice
Sound
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Communications
Wired (telephone lines, cable)
Wireless (microwaves, satellites, radio waves)
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Computer Basis
Digital
Analog
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Digital Basis of Computers
Binary CodeTwo-state
1 digit0 digit
Binary DigitBITBYTE
8 bits1 character, symbol, number
9:30
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Analog Basis of Life
Continuously variable values
Wave-like pattern
ModemModulate/Demodulate
makes possible transmission
of digital signals
over analog lines
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Modems
Converts digital signals to analog to transmit over phone lines and back to digital for the receiving computer.
Transmits up to 56K on telephone modem.
Transmits up to 2 Mbps on cable modem.
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Networks
LAN
T1 and T3 connections
Network Interface Card
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Port
A socket on the outside of the system unit connected to an expansion board on the inside of the system unit
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Parallel ports 15 ft limit Printers 25-pin connector
Serial (RS-232) COM 1 COM2 (communication ports)
mice Modems
9- or 25-pin connector
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SCSI port Faster parallel interface than regular parallel or
serial interface
Video adapter port Connects monitor
USB High-speed connections for printers, digital
cameras, scanners, etc.
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Expansion Slots & Boards
Expandability Increase computer’s capacity for adding more
memory and/or peripheral devices
Sockets on the motherboard into which you can plug expansion cards
PCMCIA Card Enables installation without rebooting system
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Miscellaneous
ErgonomicsWork environment to improve safety and
health.
Carpal-Tunnel SyndromeMedical condition, or repetitive-stress
injury.
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Surge Protectors
Guards against electric spikes.
Provides different levels. Check specs before buying!
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Types of Software
Operating SoftwareEnables computer system to run
Application SoftwareDesigned for end-users to perform tasks
Excel—electronic spreadsheetsPowerPoint—professional presentations
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Software Acquisition
FreewareNo CostAuthor ownership retained
Public DomainNot copyright protectedCan be altered for user’s own purposes.
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Open SourceVariation of freewareMachine-readable formatUseable but not can’t copy
SharewareFreely distributed for trial period onlyExpected to pay for extended use E.g., WinZip & Macromedia Dreamweaver
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Software Piracy Illegal copies of copyright-protected
softwareReason for expensive softwareStealing income for authors & companies
that produce the software
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Ethics and Legalities
Copyright ProtectionDigital Millennium Copyright Act 1998Designed to protect © owner who has
invested time and money creating software
UVSC Policies http://www.uvsc.edu/policies/admin/a-10.html
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Computer Viruses
Code that transfers from one computer to another
Continuous duplication of itself to Destroy files Clog storage devices and communication
networks
Protection Software Firewalls
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Security Concerns
Authentication Makes sure user requesting access is authorized
to do so
Password Guidelines Choose carefully Mix and match letters and numbers Change passwords often Remember your passwords! Keep passwords confidential.
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Biometric SecurityTechnology that uses biological features,
such as face-scanning, iris scanning, and fingerprints to verify authorization
Increasing implemented since 9-11.
EncryptionProcess converts data into indecipherable
code to protect sensitive information, such as credit card #s on Internet.
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Resources
Webopedia
TechEncyclopedia
NetLingo The Internet Dictionary
ComputerUser High Tech Dictionary
3D Dictionary
Prentice Hall “In the News”