What is a Computer

A Computer is…

• A monitor (output device)

• Keyboard (input device_

• CPU (The Brain)

Input Devices

http://www.elfrida.com/Web/courses%202005-2006/images/input%20devices%20big%20transparent%20small.gif

• The keyboard is the most common input device.

• The microphone inputs voice/sound recordings

• Video input allows images created by video recorders to be transferred to the computer

• The Scanner converts images into electronic form and saved to your computer

Memory

• Memory is storage—the more memory the computer has the more storage capacity– Types of memory

• RAM & ROM

• RAM—(Random Access Memory) short term memory. The more memory of this type the faster the computer processes data

• ROM—(Read Only Memory) is specific instructions that come with the computer from the manufacturer. ROM is not volatile.

Application Software

• Computer program that helps the user complete a task– Word processors– Spreadsheets– Databases

Operating System

System software responsible for control and management of hardware & basic systems operations

Starting Computer

Instructions are stored in the ROM to load the Operating System into the memory.

The Pascaline

• One of the earliest mechanical devices used for calculating,

• A complicated set of gears which could be used to perform addition and subtraction.

• Invented by the French philosopher and mathematician Blaise Pascal in 1642.

http://www.th.schule.de/th/lfk-informatik/ideen/arnoldi/pascline.jpg

Babbage’s Difference Machine

• 1822 Charles Babbage starting developing the “Difference Engine”.– This device was to calculate numbers to the 20th place

and then print them at 44 digits per minute.– Original purpose of this machine was to produce

tables of numbers that would be used by ship’s navigators

Babbage’s Analytical Engine

• The Analytical Engine 1833—used punch cards, was to store information in memory and make decisions and carry out instructions.

The Punched Card• Developed in 1810 by Joseph

Jacquard a French Weaver.• The punch card allowed weavers to

use different threads w/o stopping the machine

• The idea that information can be stored by punching holes on a card was of great use in the later development of the computer

http://www.deutsches-museum.de/ausstell/meister/img/webstgr.jpg

http://www.tonh.net/museum/punchcard.jpg

The Electronic Tabulating Machine• Herman Hollerith invented a

calculating machine in 1890 that used electricity rather than mechanical gears.

• Used to tabulate census • Holes representing information to

be tabulated were punched in cards similar to those used in Jacquard’s loom. Cards were then inserted into the machine and metal pins used to open and close electrical circuits. Friends sold his machine all over the world and this company became IBM

http://histoire.info.online.fr/images/hollerith.jpeg

ENIAC: The First Electronic Computer(1st Generation)

• 1943 Originally a secret military project which began during WWII to calculate the trajectory of artillery shells.

• Developed by John Mauchly and J. Presper Eckert– Occupied 1500 square feet (3 bedroom house)– Weighed 30 tons– Used vacuum tubes instead of relay switches– It was able to make decisions.

http://www-ivs.cs.uni-magdeburg.de/bs/lehre/wise0102/progb/vortraege/kmuecke/eniac.jpg

Computer History1. Punched cards – 1st generation2. Vacuum Tubes – 1st generation3. Transistors – 2nd generation4. Integrated Circuits – 3rd generation5. Microprocessors – 4th generation

Allowed computers to be smaller

http://www.slc.k12.ut.us/sites/horizonte/Computer%20Modules/Computer_Technology/Vocab_Images/input_output.gif

CPU controls all functions of the computer electronically without flipping switches or pulling wires

Peripheral Devices(Input/output)

•Operate outside of the PC base unit

•Add functionality

Machine Language

• Machine Language programming was done in the 50’s to 80’s.– This was how humans talked to computers– IBM set a standard universal language for

computers which is called ASCII – One byte equals 8 bits

• The Letter J in ASCII Language is 74 in Binary Code it is 01001010

Machine Language

• 0 and 1

• Works like on/off switch

• 1 = on

• 0 = off

http://computer.kiwoo.de/software_sxc.jpg

Storage Capacity

• Byte 8 binary digits (bits)

• Kilobyte KB 1024 bytes

• Megabyte MB 1000 Kilobytes (1,024,000 bytes)

• Gigabyte GB 1000 Megabytes

Storage Devices

• Diskette

• CD/DVD

• Hard Disk

• USB Drive

• iPod

Analytical Engine and Ada Byronhttp://upload.wikimedia.org/wikipedia/de/7/7e/Charles-babbage.jpg

http://www.wilsonsalmanac.com/images2/byron_ada.jpg

Analytical Engine could not “originate anything” or think.

The Web• Web Browser – software required to

receive and view information at a Web Site

• Web Site – location on the WWW where information is presented in web pages using graphics, text and sound

• Web Page – information at a web site that can include graphics, text and links to other web sites and pages.

Modem

• A device that connects a computer to a phone line. A telephone for a computer. A modem allows a computer to talk to other computers through the phone system.

http://www.callcorder.com/images/connect-to-modem.gif

What are Networks

• A group of two or more computer systems linked together. A combination of software and hardware that works together to allow computers to share data and devices. There are many types of computer networks, including:

– local-area networks (LANs) : The computers are geographically close together (that is, in the same building).

– wide-area networks (WANs) : The computers are farther apart and are connected by telephone lines or radio waves.

URL

• http://www.aol.com

• Uniform Resource Locator - unique

• Domains– com– net– gov– org

Copyright

• The exclusive right to make and dispose of literary, musical or artistic work.

Computer Crime

• Unauthorized use of or access to private information

• Investigated and prosecuted by the FBI• Virus – a program that replicates itself and

s[reads to other computers, usually destructive. It infects computer from– E-mail attachments– Spyware– Other media

Avoiding Computer Crime

• Change Password often

• Use a virus scanning program

• Don’t open unknown attachments

Network Communication

• Bandwidth – the speed at which data can travel over transmission media (bps)

• Transmission media– Cable– Wireless – High Frequency radio waves,

infrared signals

• Internet – largest and most widely accessed network