Introduction to Computers

What is a computer? An electronic device, operating under the control of instructions stored in its own memory unit, that can accept data, manipulate the data according to specified rules, produce information from the processing, and store the results for future use.

Devices that comprise a personal computer.

Inside a computer

Information Processing Cycle—four general operations Input Processing Output Storage

Input Devices Keyboard Mouse Digital camera Scanner Microphone

What are the components of the computer? Input devices Central processing unit (CPU) Output devices Memory Storage devices

Keyboards

Mouse Devices

Digital Cameras

Scanners

Microphones

Central Processing Unit Made up of the control unit and arithmetic/logic unit The brains of the CPU is the processor. There are different brands and speeds Pentium made by Intel Celeron made by Intel Athlon made by AMD

Memory RAM—also called Random Access Memory ROM- also called Read Only Memory

Processors & Memory

Role of the CPU Role: The CPU also called microprocessor, or brain of the computer, contains millions of switches and pathways to help the computer make decisions. The switches control the flow of electricity as it travels across the pathways. Computer programs are special instructions written to tell the computer which switches to turn on or off. Speed: deciding factor on which computer to purchase. The system clock is an electronic pulse used to synchronize the processing and determines the speed of the processor, measured in megahertz. The higher MHz the faster the computer.

Data Representation Byte—one character of data Kilobyte—one thousand bytes of data Megabyte—one million bytes Gigabyte—one billion bytes Terabyte—one trillion bytes Petabyte—one quadrillion bytes Exabyte—one quintillion bytes Zettabyte—one sextillion bytes Yottabyte—one septillion bytes http://www.jimloy.com/math/billion.htm

Output Devices Printers Monitors Impact printers Nonimpact printers Dot matrix printers Nonimpact printers Ink jet Laser Color B & W Monitors CRT’S LCD’S

STORAGE DEVICES Floppy Disks Hard Disks CD’s—Compact Discs DVD’s 3.5-inch disks store 1.44M of data Must be formatted Tracks sectors Hard Disks Spins at 5,400 – 7,200 rpm (revolutions per minute) Can store anywhere between 10G – 250G+ of data CD’s—Compact Discs Available in a variety of formats—CD-ROM, CD-R, CD-RW A typical CD holds about 650 MB of data DVD’s Available as DVD-ROM, DVD-R, DVD-RW Can hold 4.7 GB of data Zip Drives—high capacity floppy disk drive; has lost popularity Zip disks can hold from 100 MB – 250 MB of data USB Flash Drive Storage capacity between 32 MB – 4 GB

STORAGE DEVICES

Software—Can be categorized into four types System software Application software Educational software Entertainment software

System Software Controls the operations of computer equipment Operating System software tells the computer how to: Load Store Execute OS is loaded into memory when the computer is turned on This process is called booting Most OS’s use a Graphical User Interface (GUI) Provides visual cues such as icons Each icon represents an application

Application Software Programs that tell a computer how to produce information Commonly used applications Word processing Spreadsheet Database Presentation Financial Email Taxing

Educational Software Software that can be used for learning purposes Examples include: Jump Start Series Mavis Beacon Teaches Typing Reader Rabbit Encarta or World Book Math Blaster Rosetta Stone Spanish

Entertainment Software Sports games Madden NFL MLB The Sims World of Warcraft Rollercoaster Tycoon Final Fantasy Halo Myst Half Life Barbie Fashion Show

Types of Computers Type Size Power Purpose Supercomputers Largest Fastest processing speeds compared to other computers Cost can be several million dollars For corporations with lots of data to be processed Mainframe computers Large Less powerful than supercomputers but large compared to personal computers Can cost hundreds of thousands of dollars Performs centralized processing tasks for many users Minicomputers Larger than microcomputers but smaller than mainframe computers Same as microcomputers Used for companies with many users and large amounts of data and can run on any computer hardware Microcomputers and notebook computers Fits on a desktop Not meant for large amount of data Writing papers, tracking finances, playing games, connecting to the Internet. PDA’s, Cell phones, calculators, interactive books, digital cameras, game systems are accepted as they make everyday tasks easier to accomplish.

Binary number system Computers only understand machine language, or binary, which is ones and zeros. Through the pathways and by turning switches on and off the CPU processes ones and zeros When electricity is present it represents a one. The absence of electricity represents a zero. Coding Systems such as American Standard Code for Information Interchange (ASCII) determines which combination of zeros and ones represents the letter A or the number 1. Each one or zero is a bit, and eight bits or combinations of ones and zeros represents a byte.

Networking A network connects one computer to other computers and peripheral devices Allows computers to share: Data – special group projects, databases, etc. Hardware – printers or scanners Software – instead of purchasing programs for each individual computer, a site license can be purchased for the number of users and it is less expensive Files – collaborative, allows users to work together