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BASIC
COMPUTER
CONCEPTS
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BINARY NUMBER SYSTEM
• Computer systems work on the binary number system.
• The binary system was discovered by Mathematician
George Boolen in 1854.
• There are no numbers other than 0 and 1 in this
system.
• bn={0,1}
• 101010=1*25+0*24+1*23+0*22+1*21+0*20
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DECIMAL NUMBER SYSTEM
d=0,1,2,….,9
4137=4*103+1*102+3*101+7*100
86=(1010110)2
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HEXADECIMAL NUMBER SYSTEM
• hn=0,1,2,….,9, A, B, C, D, E
• ABCD=10*163+11*162+12*161+13*160
• Convert from hexadecimal to binary
• Hexa numbers are divided into groups of four
bits and combined
• (ABCD)16 = ( )2 ?
• A=1010, B=1011, C=1100, D=1101
• (ABCD)16 = (1010101111001101 )2
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MORE CONVERSIONS
• (1AB3)16 = ( )2 ?
• Hexa numbers are divided into groups of four
bits
• 1= 0001 A=1010 B=1011 3=0011
• (1AB3)16 = (110110101100)2
• (101110101100)2 =(BAC)16?
• Convert groups of four bits to hexa numbers
and combine 1011=B, 1010=A, 1100=C
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• Convert from decimal to hexadecimal
• (242)10 = (F2)16 (divide 242 by 16)
• Convert from octal to hexadecimal
• (121)8 = ( )16 ?
• (121)8 = ( )10 = ( )16
• 1*82+2*81+1*80 = 81 divide by 16
• Divisor=5, remainder=1 so (121)8 =(51)16
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Hardware vs. Software
Hardware
» The computer equipment
» Includes printers, monitors, disk drives, etc.
Software
» Programs which tell the computer what to
do
» Examples - word processing, gradebook,
tutorials, games, etc.
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History of Computers
Charles Babbage - father of computer
» 1800’s planned analytical engine
ENIAC - developed at end of WW II
1951 - 1963 1st and 2nd generation
» very large, used unreliable vacuum tubes
1963 - present - 3rd and 4th generation
» smaller, faster - use transistors and
integrated circuits
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History - Microcomputers
Apple
» First sold in late 1970’s
» Developed by Jobs and Wozniak
IBM Personal Computers
» First sold in 1981
» Was quickly accepted by businesses
» IBM compatibles soon developed
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Computer - Social Impact
Threat to privacy
Reduce personal interactions
Displace workers and change workplace
» Create two tiered society
Computer failures cause great damage
Artificial Intelligence
» Create a “new life form”
» Machines smarter than their creators
Types of Computers – 12
Personal Computers (PC)
Also called
Microcomputers
Available in desktop
size, notebook size and
handheld
Can be IBM, IBM
Compatible or Apple
Types of Computers - 13
Minicomputers
Size of filing cabinet
Used by small and medium size
companies and institutions
Operated by computer specialist
Terminals allow many people to use
Types of Computers - 14
Mainframes
Very powerful
Very fast
Used by large corporations and
governmental agencies
Operated by computer specialist
Types of Computers- 15
Supercomputers
Most powerful
Fastest
Most expensive
» Several million dollars each
Used only by
» Governmental agencies
» Large international corporations
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Computer Operations
Input Processing Output
External Storage
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Input Devices - Keyboard
Most commonly used input device
Ergonomic - fit natural hand placement
Special keys
» Enter, Function, Ctrl, Alt, Num Lock, Esc
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Input Devices - Mouse
Controls cursor on
screen
May be mechanical
or optical
Most models have a
“wheel” for scrolling
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Input Devices - Other
Pointers (replaces mouse on notepads)
» Track point, track ball, touch pad
Scanner
Digital camera
Touch screen
Voice
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Output Devices
Monitor
Printer
Disk Drive
» Can also be input device
Modem
» Can also be input device
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Monitors
Made up of tiny
elements called
pixels
Each row of pixels is
called a scan line
Picture is displayed
by an electronic
beam lighting up
certain pixels
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Monitors - Resolution
Resolution is how sharp and clear the
picture is
How many scan lines on the screen
– 640 x 480 is low resolution
– 1600 x 1200 is high resolution
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Monitors - Dot Pitch
Measures the distance between pixels
Commonly seen on monitors advertised
» .49 (not very good)
» .28 (much better)
» .26 or lower (excellent)
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Monitors - Sizes
Screen measured diagonally
» May also measure actual viewing area
14” or 15” on bargain systems
17” has become the standard
19 and 21” available but are more
expensive.
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Monitors - LCD
Liquid Crystal Display
Similar to digital watch
Used for notebook computers
» Should be an Active Matrix Screen
Also used in flat screen monitors
» Much thinner than regular CRT monitor
» More expensive than regular CRT monitor
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Monitors - Video Card
Processes info to send to monitor
Amount of video memory may speed up
graphic intensive programs
» 32 megs –general purpose
» 128 or more megs – graphic intensive use
AGP port can speed up graphics
3D accelerator card improves graphics
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Monitor - Buying Hints
17” or larger
.28 dot pitch or better
32 or more megs of memory on
video card
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Printers
Laser
Ink Jet
Dot Matrix
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Printers - Laser
Works similar to a copy machine
» Color printers available but more expensive
Fast, quite, with excellent quality
More expensive to buy and operate
Some units scan, photocopy, and print
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Printers - Ink Jet
Squirts small jet of ink onto paper to
form characters
Replaced dot matrix
Quiet
Does good job on color
Good quality and reliability
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Printers - Dot Matrix
Strikes pins against ribbon to print
Comes in 9 and 24 pin
Once very popular
Now replaced by ink jet and laser
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Printers - Speed
Measured in pages per minute (PPM)
Laser printers range from 20-45 ppm
» Color printing is slower
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Printers - Quality of Print
One measure is dots per inch (DPI)
» 300 dpi for general purpose uses
» 600 dpi for higher quality
» 1200 dpi for photo quality
May have different vertical and
horizontal resolution
» 600 x 300
Other factors can affect quality
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Basic Processing Cycle
Central Internal
Data
Processing Memory
Bus
Unit
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How Information Is Stored
Memory consist of switches which can be
either on or off - Off=0 On=1
Each on/off switch is called a bit
Eight bits make up a byte
It takes one byte to store a character
» Character can be letter, space, punctuation,
etc.
» ASCII code used
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Other Memory Terms
Byte is eight bits
Kilobyte (KB) is approx. 1,000 bytes
Megabyte (MB) is approx. 1million bytes
Gigabyte (GB) is approx. 1 billion bytes
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Central Processing Unit
Also called CPU, processor or
microprocessor
Is the “brains” of the computer
Performs all computer operations
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CPU - IBM COMPATIBLES
Many made by company called Intel
Also made by AMD
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Pentium class processors
Needed to run most current software
Intel – Celeron or Pentium IV
AMD
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CPU - Clock Speed
Number of “cycles” per second
computer can operate
Measured in megahertz (MHz)
One MHz = 1 million cycles per second
One gigahertz(GHz)=1 billion cycles
Current speeds 2-4 GHz
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CPU - Misc.
Performance also affected by speed of
data bus
» 400-800 MHz on most current systems
Cache can increase speed
» Stores data you will likely need next in an
area that has faster access
» Both memory cache and disk cache used
» Should be 512 K or better
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CPU - Buying Hints
Minimum of Pentium IV or AMD Athlon
Minimum of 2 GHz clock speed
Minimum of 512K of cache
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Internal Memory - RAM
RAM - Random Access Memory
» CPU can access any location as quickly as any
other
Can not only read current info but also write
new info
Very important in determining capabilities of
the computer system
Computer should have at least 256 megs -
512 preferred (can add to later)
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Internal Memory - ROM
ROM - Read Only Memory
» Can read info Stored in ROM
» Can not write new info into ROM
Used for “internal workings” of computer
Buyer is not very concerned with ROM
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External Memory
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Floppy Drives
Comes in 5 1/4” and 3 1/2”
» All systems now only have 3 1/2”
HD - High density - comes on all current
systems
» 3 1/2” - 1.44 megs
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Hard Drives
Builtinto machine
Made up of stack of platters
Can store much more than floppy
drives
» 40 gigabytes should be minimum
Can access info much faster than
floppy drive
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CD ROM
Same as music CDs
Are read only
Can store over 650 megs
All programs now only sold on CD
Make multimedia possible
Come in different speeds - 20x, - 50x
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DVD-ROM
Digital Video Disk
Can store up to 17 GB
Can store full-length movies
Can also read CD-ROM disk
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CD-RW & DVD-RW DRIVES
Allows you to write to disk
Useful for
» Data backup
» Storage of large files
» Recording music and other multimedia files
DVD-RW
» Allows you to write to both CD and DVD disk
» Still somewhat expensive
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Storage Devices - Other
USB drive
» Very popular – 64-512 MB
Tape drive
» Similar to cassette tape
» Used for backup
Zip drive
» 100 MB to 2 GB capacity
» Everyday use and backup
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Drives - Buying Advice
40 gigabyte hard drive
One 3 1/2” high density floppy drive
CD-RW drive
DVD not yet essential but useful
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Expansion Slots
Allows you to add capabilities
Example of cards you can add
» Network card
» Modem
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Ports
Connects computer to another
device
Parallel port
» Used primarily by printers
Serial ports
» Modem, mouse, etc.
SCSI - chain devices
USB –may be needed for
» Digital Cameras
» Mp3 players
» Other devices
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Networks
Connects computers
LAN - Local Area
WAN - Wide Area
Wireless
Allows sharing of
programs, files,
printers, etc.
Server is “main”
computer
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Modems - General
Allows 2
computers to
communicate over
phone lines
Can be internal or
external
Can also have fax
capabilities
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Modems
Bits per second(bps) indicates speed
» Old modems - 9,600, 14,400, 28,800, 33,600
» 56,000 (56K) has becoming standard
Ways of connecting to the Internet
» Dial-up modem – used in most homes
» Cable modem – uses TV cable lines
» DSL – modified phone line
» T1 line – used by schools, businesses, etc.
Min Hardware 58
Requirements
2 GHz Pentium IV Class Processor
1-2 GB of RAM
17”, .28 dot pitch monitor with 32 meg card
40 gigabyte hard drive
CD-RW
56k modem
Ink jet or laser printer
Buying Hints - Software 59
Bundles
Many systems come with software included
Productivity
» Microsoft Works
» Microsoft Office, Lotus SmartSuite, etc
» Quicken, Money, or other financial software
Reference
» Microsoft Encarta or Compton’s encyclopedia
Games
Buying Hints - Service and 60
Warranty
1 year warranty on parts and labor
Optional extended warranty
30 day return policy
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Programs
Set of instructions to the computer
Programming languages
» Machine language
» Assembly language
» Procedural languages
– Basic, Fortran, Cobol
» Object oriented languages
– Visual Basic, C++, C#, Java
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Systems Software
Run fundamental operations
» Loading and running programs
» Saving and retrieving data
» Communicating with printers, modems, etc.
Examples of systems software
» DOS
» Windows 3.1, 95, 98, Me, 2000, and XP
» Unix
» Linux
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Applications Software
Helps you to accomplish a certain task
Examples
» Word processing - memos, reports, etc.
» Spreadsheets - budgets, etc.
» Database - search, sort, select data
» Educational - simulations, practice
» Graphics - charts, diagrams
» Desktop publishing - pamphlets, etc.
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Software - Legal Issues
Commercial software
» Can only make backup copies for yourself
» Can only use on one machine at a time
– Site license - use on more that one machine
Shareware
» Can use - make copies and give to anyone
» Should pay if you continue to use
Freeware – can copy and use indefinitely
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Software Viruses
Illegal code added to a program
May spread to many computers
» Copy files from one computer to another
» Download files by modem
» E-mail attachments
Virus may be relatively harmless
» Writes “You’ve been stoned” on screen
Virus may also be very damaging
» Erases everything on hard drive
Virus may activate on a certain date
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Virus Protection
Be careful where you copy files from
Do not open e-mail attachments unless
you are sure that it is safe
Use virus protection program
» Detects and removes illegal code
» Should be updated often
BASIC COMPUTER
CONCEPTS
End of Slide Show
