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Introduction to Computers

Lecture Outline

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Computer:

• An electronic device• Operates under the control of instructions

(programs) stored in its memory• Accepts information and instructions from a

user (input)• Manipulates the data according to specified

rules (process)• Displays information (output) from the

processing• Stores the results for future use

Types of Computers continued:

• Personal Computer (PC)- used by 1 person in a home or office

• Desktop- sits compactly on a desk and run on power from an electric wall outlet, not portable

• Notebook/Laptop- small, lightweight, and portable

• Tablet- portable, but user can write with a stylus (Dr.’s office/hospital)

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Types of Computers Continued:

• Mini Notebook- smaller and lighter than ordinary notebooks

• Netbooks- a type of subnotebook, designed to allow users to access Internet and check email

• Slate computers- do not have an external keyboard or mouse. Use touch screen or stylus (electronic books)

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Types of Computers Continued:

• Handheld computers- designed to fit in palm of your hand and run on batteries (smart phones)

• Smartphone- phone, address book, appointments, calculator, notepad, email, internet, music, photos/video, some word processing.

• MP3 players- handheld computer primarily stores/plays music.

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Types of Computers continued:

• Mainframe computers- used by larger business and government agencies to handle large volumes of data

• Supercomputers- as physically large as grown person, developed for high-volume computing such as weather prediction

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4 General Operations of a computer that comprise the

“Information Processing Cycle”:

Input

Process

Output

Storage

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Data:

• The collection of raw facts, figures, symbols (numbers, words, figures, graphics, video, sounds) obtained during the input operation

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Information:

• Data that is organized, useful, meaningful. Obtained thru output operation

• 55?????

• Test score

• Driving speed

• Percentage of correct answers on ACT

• Free Throw percentage

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Computer System:

• Includes hardware an software

• Hardware- physical components (screen, keyboard, mouse)

• Software- not visible, made up of programs

• Programs- instructions the computer needs to perform specific tasks

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5 Primary Components of a Computer:

• Input Devices

• CPU (Central Processing Unit)

• Memory

• Output devices

• Storage devices

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(1) Input Devices:

• Any hardware component that allows you to enter data, programs, commands, and user responses into a computer

• EXAMPLES:• Keyboard• Mouse• Digital camera• Scanner• Microphone• Touch pad (laptop)• Pointing stick (laptop)• Touch screen

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(2) CPU/Tower/Hard Drive:

• Contains the electronic circuits that cause processing to occur

• “The Brain”

• 2 components of the CPU:

• Control unit (interprets instructions)

• Arithmetic/logic unit, or ALU (performs processes)

Binary Data Representation:

• American Standard Code for Information (ASCII) pronounced “As-key”- translates the decimal numbers 0-255 into binary data.

• You may type the letter “a” on your keyboard, but the computer translates that as 01100001

• In other words, computer language!

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(3) “RAM” or Random Access Memory:

• Consists of electronic components that store data including numbers, letters of the alphabet, graphics, and sound.

• Short-Term memory that’s not permanently stored• Examples:• Bit- binary digits that create a character• Byte- stores 1 character• Kilobyte- stores 1,000 characters (or 1 double-spaced

typed page)• Megabyte- stores 1,000,000 characters (500 pages of

text)• Terabyte- stores 1,000,000,000 characters

Memory vs. Storage:

• Memory- is short term and occurs on circuits within the motherboard

• Storage- permanently kept on your computer hard drive

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Types of RAM:

• Synchronous dynamic random access memory (SDRAM)- ram synchronized with the processor to allow faster access to its contents

• Cache “cash” memory- a high speed memory chip on motherboard, computer can access cashe quicker than regular RAM

• Virtual memory- space on storage device that acts as extra RAM when you have used up all your RAM

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ROM (Read only memory):

• A chip on the motherboard prerecorded with instructions the computer uses to check its components to ensure they are working and to activate the software that provides the basic functions of the computer when you turn it on.

• Boot process-set of events that happens from the time you turn on computer to the time you can use your computer

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Processing Hardware:

• Motherboard- the main board inside your computer that contains major electronic components. Looks like a city as you look down from an airplane.

• microprocessor/ processor/CPU- transistors and electronic circuits on a silicon chip

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Processors: How Fast?

• Megahertz- pulse of the processor, millions of cycles per second

• Gigahertz- billions of cycles per second• Single core processor- one processor on a

chip• Dual core processor- two processors on a

single chip• Quad core processor- 4 processors on a

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(4) Output Devices:

• Makes the information resulting from processing available for use

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Output Device Examples:

• Printer

• Monitor– LCD(liquid crystal display) manipulates light

within a layer of liquid crystal. Difficult to view from an angle.

– LED(light emitting diode) more energy efficient than LCD. Uses diode crystals to provide light

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2 Types of Printers:

• Impact printer:• Prints by striking an

inked ribbon against paper

• Example: dot matrix, PIN printers

• Non-Impact Printer:• Forms characters by

means other than striking a ribbon against paper

• Example: ink jet, laser printers

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Advantages of Non-Impact Printers:

• Higher quality text/graphics

• Different fonts

• Quieter

• Prints in color

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(5) Storage Devices:

• Used to store instructions and data when they are not being used in memory.

• 3 types of storage devices in PC’s:

• USB Flash Drive/memory card

• Hard disks (CPU)

• CD/DVD’s

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Storage Devices cont’d:

• Flash Drive • A magnetic storage device

• Storage capacity of 1 to 64 GB of memory

• Portable• Inexpensive storage

medium• About the size of a pack

of gum

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Storage Devices cont’d:

• Hard Disk • A magnetic storage device

• Storage capacity measured in gigabytes or terabytes

• Contains one or more rigid metal platters coated with metal oxide

• Not repairable, must replace

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Storage Devices cont’d:

• Compact Discs • Optical storage device

• Flat, round, portable, metal storage medium

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ROM:

• Compact Disc-Read Only Memory (ROM)

• Can only read the contents of these discs

• Cannot erase or modify their contents

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CD-R:

• Compact Disc-Recordable

• Writes on part of the disc at one time and another part at a later time

• Can write on each part only one time

• Cannot erase the disc’s contents

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CD-RW:

• Compact Disc-ReWriteable

• Erasable disc you can write on multiple times

• Acts like a floppy disk or hard disk

• Allows you to write and rewrite data, instructions, and information onto it multiple times

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DVD-ROM

• Digital Video Disc-Read Only Memory

• Storage capacity from 4.7 GB to 17GB

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2 CATEGORIES OF COMPUTER SOFTWARE:

• System software

• Application software

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(1) Operating/System Software:

• Consists of programs to control the operation of computer equipment—”operating system is the most important of the software!”

• Example: Windows/Snow Leopard

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4 Facts about System Software:

• Tells the computer how to perform the functions of loading, storing, and executing an application program and how to transfer data

• Must be stored in the computer’s memory• Must be loaded into memory from an auxiliary

storage when the computer is turned on• Most operate under a GUI (graphical user

interface)- acts as a liaison between the user and all of the computer’s hardware and software

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(2) Application Software:

• Consists of programs that tell a computer how to produce information

• Examples:• Word processing Software: used to create, edit, format,

and print documents• Spreadsheet Software: allows user to add, subtract, and

perform user-defined calculations on rows and columns of numbers

• Database Software: allows the user to enter, retrieve, and update data in an organized and efficient manner

• Presentation Graphics Software: allows the user to create documents called slides to be used in making presentations

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Network:

• A collection of computers and devices that are connected

• Must have network software- Microsoft home edition doesn’t have, Professional does

• Standalone- a PC not connected to network

• Workstation- a PC connected to network

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4 Reasons to Network Computers:

• Sharing Resources/Hardware Devices (printers)

• Sharing Software

• Sharing Data

• Sharing Information

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Networking Advantages:

• Saves Time

• Saves $$$

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2 Basic Types of Networks:

• LAN (local area network: connects computers in a limited geographic area

• Examples:• School computer

labs, office, or group of buildings

• WAN (wide area network): connects computer in a large geographical area

• Examples:• District offices of a

national corporation

Other types of Networks:

• WLAN- wireless LAN. Uses radio waves• Wi Fi- Wireless Fidelity radio frequency but short

distances (building)• PAN- personal area network. Devices located

close to each other, usually by cable but can use Wi-fi.

• Bluetooth- radio waves to connect to devices or internet. Goes around corner and through wall

• WiMax- allows you to connect to a LAN from long distances

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INTERNET:

• Worldwide collection of networks that links together millions of computers by means of (1) modem, (2) telephone lines, (3) cables, and (4) other communications devices and medias.

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Reasons to use the Internet:

• Sending messages to other connected users (e-mail)

• Accessing a wealth of information

• Shopping for goods and services

• Meeting or conversing with people around the world

• Accessing sources of entertainment and leisure

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2 Ways to Connect to the Internet:

• Internet Service Provider (ISP): organization that supplies connections to the Internet for a monthly fee

• Online Service: provides access to the Internet and a variety of other specialized content and services

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WORLD WIDE WEB (www):

• Contains billions of documents called web pages

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Web Page:

• A document that contains text, graphics, sound, and/or video

• Has built-in connections, or hyperlinks to other web documents

• Stored on computers throughout the world

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Web Site:

• A related collection of Web pages

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Web Browser:

• Software program used to access and view web pages

• Browser Examples: (1) Microsoft Explorer (2) Firefox, (3) Safari, (4) Google Chrome

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Uniform Resource Locator (URL):

• The unique address of a web page

• Must be typed on the address bar

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Web Server:

• A computer that delivers requested web pages

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3 Types of E-Commerce:

• B2C- Business to Consumer: Sale of goods to the general public

• C2C- Consumer to Consumer: one consumer selling directly to another

• B2B- Business to Business: provides goods and services to other businesses

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Security threats :• Virus- harmful programs

which instruct your computer to perform annoying or destructive activities (worms and Trojans)

• Spyware- secretly tracks you Internet usage and sends data back to person who created it

• Malware- any program that is intended to cause harm or convey information to others w/o owner’s permission

• Adware- program installed along with another program that sends targeted ads

Security Threats:

• Phishing- when you receive a hoax email and click on their link to go to a false web site in hopes of gaining personal information

• Spoofed site- a web site set up to look exactly like a legitimate web site (banking, credit card, etc.)

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Antivirus Software:

• Searches executable files for the sequences of characters that might cause harm and disinfects the files by erasing/disabling those commands

• Anti Spyware- detects and deletes program

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Cloud Computing:

• Data, applications, and even resources are stored on servers accessed over the Internet rather than on individuals computer hard drives

• Carbonite, Mozy

• Google Docs

• Microsoft Web Apps

• SkyDrive

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DYK (Did you know) the different meanings of website

extensions?• .com = commercial company

• .net = network

• .org = organization (non-profit)

• .gov = government

• .edu = education

• .mil = military