Transcript 01computerOLD

Introduction To Computers
What Is A Computer?

A programmable machine
– Responds to a specific set of
instructions in a well-defined
manner.
– Can execute a prerecorded list of
instructions (a program)
CLR DATA DEF FN
DIM END
FOR...TO...STEP GET
GOSUB GOTO
IF..THEN INPUT LET
NEXT ON PRINT
READ REM STOP
WAIT
10 PI = 0: C = 1
20 PI = PI + 4/C +
4/(C + 2)
30 PRINT PI
40 C=C+4: GOTO 20
What Is A Computer? Textbook
An electronic device that
– Accepts data (raw facts)
– Processes that data
– Produces meaningful information
» Through math / logic
» Without human intervention
DATA  INFORMATION
Which Computer is Best?
A.
B.
C.
D.
Dell
Gateway
HP/Compaq
IBM
VOTE!
Which Computer is Best?
Apple (298)
9.2
Alienware (58)
8.8
Self-built (1,408)
8.4
Sony (445)
8.2
Clone (710)
8.2
Shuttle (63)
8.0
Dell (5,752)
7.9
MPC/Micron (82)
7.8
Gateway (688)
7.7
Systemax (92)
7.7
eMachines (367)
7.4
HP/Compaq (2179)
7.4
Lenovo/IBM (334)
7.4
Need A Computer?

Find the
cheapest Dell
computer
Apple (298)
$500 (mini) +
monitor
Alienware (58)
$659
Self-built (1,408)

Build it yourself
-
Sony (445)
$700 + mon
Clone (710)
Shuttle (63)
Dell (5,752)
TINY!
$600 + mon
$300
Which Computer Is Best?

2002 PC Magazine Reader Survey
Which Computer Is Best?

2003 PC Magazine Reader Survey
2004 PC Mag Reader Survey
2005 PC Mag Reader Survey
What Do Computers Do?

Computers perform 4
general operations:
• Input
• Processing
(arithmetic / logical)
• Output
• Storage
All of the following are widely
used input devices except __
A. keyboard and mouse
B. microphone and scanner
C. printer and monitor
D. digital camera & PC video camera
VOTE!
Input Devices
 Keyboards
 Mouse
Others?
Processor Unit

Consists of two parts:
– Central processing unit (CPU)
– Main computer memory (ram)
ASUS A7N266

Processor:
–

RAM:
–

Samsung 700NF
Hard Drive:
–

Lite-On LTR-52246S
Monitor:
–

US Robotics 56K V90 PCI
CD-RW:
–

On board
Communications:
–

ATI Radeon 9100 64MB Retail
Sound, Network
–

256MB PC2700 DDR
Video:
–

AMD Athlon XP1900+ OEM
Seagate Barracuda ATA V 60GB
TOTAL: $650
Central Processing Unit
CPU

Brain of the computer
– 8080 cpu
8 bit processor
8086 cpu
16 bit processor
80286 cpu 16 bit processor
80386 cpu 32 bit processor
80486 cpu 32 bit processor
Pentium cpu 32 bit processor
Pentium II-III 32 bit processor
Pentium IV 64 bit processor
Ce le ron
Transistors
7,500,000
Pe ntium II
7,500,000
Pe ntium III
9,500,000
333 MHz 500 MHz
300 MHz 450 MHz
450 MHz 866 Mhz
128 KB,
512 KB,
512 KB,
f ull speed
half speed
f ull speed
66 MHz
100 MHz
133 MHz
Floating
Point
strong
strong
strong
Integer
strong
strong
strong
CPU Speed
L2 Cache
Front-Side
Bus Speed
Memory
Main computer memory
 Random access memory

– RAM

Measured in bytes (chars)
– KiloBytes
– MegaBytes
– GigaBytes
1000
1 million
1 billion
Bit Permutations
1 bit
0
1
2 bits
00
01
10
11
3 bits
000
001
010
011
100
101
110
111
4 bits
0000 1000
0001 1001
0010 1010
0011 1011
0100 1100
0101 1101
0110 1110
0111 1111
Each additional bit doubles the number of possible permutations
19
All of the following are widely
used output devices except __
A. display devices (screen/monitor)
B. speakers and headsets
C. printers
D. ports
VOTE!
Output Devices
Printers
 Impact
»Daisy wheel
»Dot matrix
 Non-impact
»Laser
»Ink jet

Laser Printer
Monitors
CRT vs. LCD
 MONOCHROME
vs. Color
 Pixels

–
–
–
–
640 x 480 VGA
800 x 600 super VGA
1024 x 768 “
“
1280 x 1024 “
“
Pixel
Auxiliary Storage

Storage of data and
programs when not
stored in main
memory
 Diskettes
– 5 1/4”
– 3 1/2”
– Double sided, SS
– Double or high density
Hard Drives
(Fixed Drives)

Capacity measured in
megabytes

Size 100s MB to
100GB
Disk, Track, Sector

Track.
– A ring on a disk where
data can be written.

Sector.
– The smallest unit that
can be accessed on a
disk.
CD-ROM






Compact disk-read only
memory
600 meg
22K tracks
Software distributed on CD
Multimedia software
CD-recorders available
– Read and write to them
Computer Software


-System software
– Operating system
– Diagnostic
Application software
– Word processing
– Spreadsheets
– Database management
– Business payroll, etc.
– Games, et. Al.
Dos





Microsoft’s Disk Operating System
First version 1.0.
– Whole number is version
– decimal number is release
Minor upgrades are releases. (1.2, 1.3, 1.4, etc...)
Complete revisions use a higher whole number.
DOS is upward compatible
– software running with an older version (3.0)
should run with a newer version (6.22)
Windows Version

Graphical user interface (GUI).
– Uses graphics and text to communicate with user.
(Contrast with DOS prompt).

Windows 3.1, 3.11.
– A GUI.
– Not an operating system.
– DOS is still required.

Windows 98, XP
– An operating system.
– Includes a GUI.
Communications

Transmission of data over
communications channel
such as telephone lines
Communications Equipment



Computers process data using digital signals.
Telephone equipment uses an analog signal.
Modem.
– Converts the digital signals of a computer to an
analog signal and vice versa.
– Data can be transferred from one computer to
another using the telephone lines.
Internet Service Provider

ISP
– provide subscribers with software necessary for
communications
» Dixie-Net
» CrossRoads
» Network One
The Internet
The network of worldwide computers.
 World wide web (WWW).

– Allows users to use text, graphics, video and
sound from other web sites on the internet.

Browsers.
– Allow users to browse volumes of information
from computers around the world.
– Netscape navigator, internet explorer.
Networks

LAN
– Local Area Network

Computers in Same
Buildings or Close
Buildings Connected
Through Cables.
WAN

WAN (Wide Area
Network)
– Computers Connected
Thorough
Communications
Channels Such As
Telephone Wires,
Microwaves, Etc.
Considerations for Purchasing a Computer
Determine what it will be used for.
 Choose your software first.
 Beware of hidden costs.
 Compare purchases alternatives.
 Consider the advantages of buying locally
and from direct mail order companies.

Purchasing Continued
Look for free software.
 Purchase a system compatible with the one
you use elsewhere.
 Consider an on-site service agreement.
 Use a credit card for purchasing your
system.
 Plan to use the system for at least 3 years.

Installing a Computer System








Allow for adequate work space.
Install computer in a well-designed work area.
Provide adequate lighting.
Install or move a phone near the computer.
Save all paperwork that comes with your system.
Record the serial numbers of all equipment and
software.
Keep all shipping containers.
Install in area where temperature and humidity can
be maintained.
Computer Viruses

A computer program designed to infect computer
systems by copying itself into other computer files.

The virus program spreads when infected files are
executed on host and perhaps copied to another
system.

Installing an anti-virus program on your
computer.

An anti-virus program activates when the
computer is turned on.

Login
– Word, Excel Access, PowerPoint