Basic Computer Concepts
Mrs. Sheila M. Thompson
Woodland Hills High School
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1
What Is a Computer?
An electronic device that can perform tasks and
calculations based on the instruction it has been
given.
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Microprocessor
Internal Memory
Auxiliary Storage
Input Units
Output Units
How Computer Works
• Accept inputs from a
person or another
outside source
• Interpret and process
the input data
• Display the results or
perform an action
based on the input
data or command
Types of Software
• System software – which controls the
way the computer parts work together.
• Application software – tells the
computer how to perform a specific
task.
Any Computer System
Memory
Central processing unit
(CPU)
Input
Output
Auxiliary Storage
Disk
Disk
Types of Computers
• Personal Computer (PC)
• most common used in
homes, offices and schools
• Small, relatively
inexpensive, individual
user.
Types of Computers
• Minicomputers - Server
• Smaller than a mainframe and larger than a
microcomputer.
• Medium-sized companies – accounting, advertising,
and manufacturing firms
Types of Computers
• Supercomputer
• Largest, fastest; 50–1,500 times faster than PCs
• Cost prohibitive – used by largest firms,
government agencies and universities.
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Types of Computers
• Mainframe computers
• Larger, more powerful than microcomputers
• Large capacity to store & manipulate data
• 10 – 40 times faster, but $100,000-$2,000,000
Internal Memory (RAM)
• Temporary (erased when power turned off)
• Measured in bytes
• 1 Byte = 1 character (8 bits)
• 1 Kilobyte = 210 (~1,000 bytes)
• 1 Megabyte = 220 (~1,000,000 bytes)
• 1 Gigabyte = 230 (~1,000,000,000 bytes)
• Need 128Mb of RAM
• Keep multiple programs & data files in memory
• Graphic-intensive programs demand a lot of
memory
Read-only Memory (ROM)
• Computer memory on which data has
been recorded on a ROM chip
• Can be read, but cannot be deleted
• Preserves its contents even when the
computer is shut down
• Stores critical programs – needed for
system start-up
The System Unit
Box-like case that
contains computer’s
electronic
components
v Sometimes called
the chassis
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The System
What are common components inside the system unit?
• Processor
• Memory
• Expansion Card
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Sound Card
Modem
Video Card
Network interface
Card
Back of the Computer
• Cooling Fan
• Power Supply
• Keyboard Connector
• Mouse Connector
• Parallel Printer Port
• Video Connector
Inside the Computer
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CD-ROM
CPU
Expansion slots
Floppy drive
Hard disk
Memory chip
Motherboard
Power supply
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Central Processing Unit (CPU)
Interprets and
carries out basic
instructions that
operate a computer
 Also called the
processor
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Motherboard
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Main circuit board in system unit a contains chips,
integrated circuits, and transistors also called
system board
Microprocessor
• Brain of the computer
• Current chips for PC
• Intel (Celeron, Pentium III, and soon-to-be
announced Pentium IV)
• AMD (K-6 and Athlon)
• Which do I buy?
• Pentium or Athlon for graphic-intensive
programs
• K-6 or Celeron for business and Internet
browsing
http://videos.howstuffworks.com/podtech-networks/2480-how-the-newestmicroprocessors-work-video.htm
Hard Disks
hard disk
installed in
system unit
• High Capacity Storage
• Consist of several
inflexible, circular
platters that store items
electronically
• Components enclosed
in airtight, sealed case
for protection
Input Devices
• Feed data into computer
• Keyboard - most commonly used input
device.
• Mouse, pointing stick, trackball, light pen,
puck and touch pad
• Opitical Character Recognition – OCR –
scans printed pages and translates
characters and images into a file that can be
edited using word processing.
• Scanner – a device that can read text or
illustrations and transmit into digital format
Input Devices
• Digital Camera – captures images in
memory storage without using film.
• Microphone – accepts voice input to
enter data or execute commands.
Output Devices
• Printers – devices that
print text or graphic onto
paper.
• Impact printer – uses a
device that strikes a
ribbon
• Non-impact printers –
use laser and ink-jet
technology.
• Speakers are input and
out put devices
Monitor Size and Resolution
• Monitors come in different sizes:
17,” 19,” and 21”
• Resolution is expressed in
pixels (such as 800 x 600 or
1024 x 768)
• The higher the resolution, the
more you can see. Larger
monitors let you run at higher
resolutions: e.g., 19” to run 1024
x 768 comfortably
• A graphics card (video display
adapter) speeds processing
Storage Devices
• Hard Drive – an internal storage
device, also known as a fixed disk.
• Flash drives – durable, rewritable hard
drives, can easily fit in a pocket or on
a chain.
• Jump drives
• Thumb drives
• Digital Audio Tape – standard
magnetic tape that resembles a basic
audio cassette.
Auxiliary Storage (Permanent)
• High Capacity Removable Storage
• Zip disks (100 or 250Mb)
• Jazz Disks (1 or 2Gb)
• Hard (Fixed) Disk
• Most common are 10 –30Gb
Auxiliary Storage (Continued)
• CD-ROM
650Mb
• Recordable devices also available
• DVD drives
4.7Gb-17Gb
• ROM and RAM
• Higher capacity than CD
• Tape Units
• Used for large, unattended back-ups
What is a CD-ROM?
• Compact disc that uses
same laser technology as
audio CDs for recording
music
• Cannot erase or modify
contents
• Typical CD-ROM holds about
650 MB
v Commonly used to distribute
software and games
CD-R and CD-RW
What is a CD-RW
(compact discrewritable)?
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Erasable disc you can write
on multiple times
Must have a CD-RW disc,
CD-RW software,
and CD-RW drive
Purchasing Decisions
• Local store versus mail order
• Magazines
• Internet
• Use credit card to double warranty
• 30-day price guarantee
• Don’t forget the software
• Windows XP, Windows Vista
• Microsoft Office (check the version)
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The PC Today
• Main Components
• 1Gb microprocessor
• 1028 Mb RAM
• 250 Gb hard drive
• 1 floppy drive
• Zip drive
• DVD-ROM drive
• 21” monitor
• 64Mb graphics card
• Other Components
• Cable modem
• CD-RW drive
• Camera
• Microphone
• TV adapter
• Sound card/speakers
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Software
• System Software
• Microsoft Windows - Operating System
• Home – Windows 98, Windows Me, windows XP
Media Center, Windows XP Professional
• Business – Windows NT, Windows 2000
• Antivirus and file compression is not built into
Windows
• Application Software
• Microsoft Office
• Word, Excel, Access, PowerPoint, Publisher, and
Photodraw
• Different editions contain different applications
Purchasing on the Web
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www.dell.com
www.gateway.com
www.ibm.com
www.pcwarehouse.com
www.microwarehouse.com
Essential Computing Concepts: Getting
32