Introduction To Computers What is a computer? What Is A Computer? n A programmable machine...
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Transcript of Introduction To Computers What is a computer? What Is A Computer? n A programmable machine...
Introduction To ComputersIntroduction To Computers
What is a computer?What is a computer?
What Is A Computer? 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? TextbookWhat 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?Which Computer is Best?
A. Dell
B. Gateway
C. HP/Compaq
D. IBM
VOTE!
Which Computer is Best?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?Need A Computer?
Find the cheapest Dell computer
Build it yourself
Apple (298)$500 (mini) +
monitor
Alienware (58) $659
Self-built (1,408) -
Sony (445) $700 + mon
Clone (710) -
Shuttle (63) TINY! $600 + mon
Dell (5,752) $300
Which Computer Is Best?Which Computer Is Best? 2002 PC Magazine Reader Survey
Which Computer Is Best?Which Computer Is Best? 2003 PC Magazine Reader Survey
2004 PC Mag Reader Survey2004 PC Mag Reader Survey
2005 PC Mag Reader Survey2005 PC Mag Reader Survey
2008
What Do Computers Do?What Do Computers Do?
Computers perform 4 general operations:• Input
• Processing (math / logical)
• Output
• Storage
A. keyboard and mouseB. microphone and scannerC. printer and monitorD. digital camera & PC video camera
VOTE!
All of the following are widely used input devices
except __
All of the following are widely used input devices
except __
Input DevicesInput Devices
Keyboards
Mouse
Others?
Other Input DevicesOther Input Devices
System UnitSystem Unit
System Unit System Unit
ASUS A7N266ASUS A7N266
Processor:– AMD Athlon XP1900+ OEM
RAM:– 256MB PC2700 DDR
Video:– ATI Radeon 9100 64MB Retail
Sound, Network – On board
Communications:– US Robotics 56K V90 PCI
CD-RW:– Lite-On LTR-52246S
Monitor:– Samsung 700NF
Hard Drive:– Seagate Barracuda ATA V 60GB
TOTAL: $650
Processor UnitProcessor Unit
Consists of two parts:– Central processing unit (CPU)
– Main computer memory (ram)
MemoryMemory
Main computer memory Random access memory
– RAM
Measured in bytes (chars)– KiloBytes 1000– MegaBytes 1 million– GigaBytes 1 billion
22
Bit PermutationsBit Permutations1 bit
01
2 bits
00011011
3 bits
000001010011100101110111
4 bits
00000001001000110100010101100111
10001001101010111100110111101111
Each additional bit doubles the number of possible permutations
A. display devices (screen/monitor)B. speakers and headsetsC. printersD. ports
VOTE!
All of the following are widely used output devices
except __
All of the following are widely used output devices
except __
Output DevicesOutput Devices
Printers Impact
»Daisy wheel
»Dot matrix Non-impact
»Laser
»Ink jet
Laser PrinterLaser Printer
Output DevicesOutput Devices
Display Devices (monitors or Display Devices (monitors or screens)screens)
MonitorsMonitors
CRT vs. LCD MONOCHROME
vs. Color Pixels
– 640 x 480 VGA
– 800 x 600 super VGA
– 1024 x 768 “ “
– 1280 x 1024 “ “
PixelPixel
Auxiliary StorageAuxiliary Storage
Storage of data and programs when not stored in main memory
Storage devicesStorage devices –1. Floppy disks1. Floppy disks
–2. Zip disks2. Zip disks
3. Hard disks3. Hard disks
A.A. Magnetic disksMagnetic disks
Diskettes
– 5 1/4”
– 3 1/2”
– Double sided, SS
– Double or high density
Hard Drives (Fixed Drives)Hard Drives
(Fixed Drives) Capacity measured in
megabytes or terabytes
Size to 5TB
Disk, Track, SectorDisk, Track, Sector
Track.– A ring on a disk where
data can be written.
Sector.– The smallest unit that
can be accessed on a disk.
Storage devicesStorage devices
B.B. Optical DisksOptical Disks–2. DVDs2. DVDs
–1. CD s1. CD s
CD-ROMCD-ROM
Compact disk-read only memory
600 meg 22K tracks Software distributed on CD Multimedia software CD-recorders available
– Read and write to them
Storage devicesStorage devices
C.C. TapeTape D.D. Miniature Storage MediaMiniature Storage Media
Computer SoftwareComputer Software
-System software
– Operating system
– Diagnostic Application software
– Word processing
– Spreadsheets
– Database management
– Business payroll, etc.
– Games, et. Al.
Windows VersionWindows 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.
CommunicationsCommunications
Transmission of data over communications channel such as telephone lines
Communications EquipmentCommunications 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 ProviderInternet Service Provider
ISP – provide subscribers with software necessary for
communications » Dixie-Net
» CrossRoads
» Network One
The InternetThe 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.
NetworksNetworks
LAN
– Local Area Network
Computers in Same Buildings or Close Buildings Connected Through Cables.
WANWAN
WAN (Wide Area Network)– Computers Connected
Thorough Communications Channels Such As Telephone Wires, Microwaves, Etc.
Considerations for Purchasing a ComputerConsiderations 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 ContinuedPurchasing 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 SystemInstalling 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 VirusesComputer 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