1. What is a Computer?
A computer is an electronic device operating under the control of instructions stored in its own memory unit, that can accept data (input) process the data and generate results (output) and store the results for future use.

2. Hardware & Peripheral devices
The electric, electronic, and mechanical equipment that makes up a personal computer is called hardware.
Devices that surround the system unit (i.e., the keyboard, mouse, speakers, monitor, and so on) sometimes are known as peripheral devices.
other devices (such as a scanner) that could be part of a computer system.

3. Information Processing Cycle
Four general operations of computer
Input
Process
Output
Storage

4. Data Vs Information
Data is a collection of raw facts, figures, and symbols, such as numbers, words, images, video and sounds
Data is given to computer during the input operation
Computers manipulate the data and produce organized, meaningful and useful information

5. Processing speed
Today’s supercomputer can perform 1.8 trillion operations per second.
If a person did one arithmetic operation a second without stopping, it would take more than 31,000 years to perform the number of operations a supercomputer can do in one second.

6. Computer users, end users or just users
People who use the computer directly or use the information it generates are called computer users, end users, or sometimes, just users.

7. Why is a computer so Powerful?
The power of a computer comes from its ability to perform the information processing cycle quickly, reliably (low failure rate), and accurately.
capacity to store large amounts of information
ability to communicate with other computers

8. Computer Program or Software
A detailed set of instructions that tells computer exactly what to do to perform an operations are called a computer program or software.
What is the difference between hardware and software?

9. Hardware Vs Software
A 3.5 inch floppy disk is a hardware but the program that is stored in a floppy disk is a software
Computer programs are written using programming languages (such as BASIC, COBOL, C, Pascal, and so on) each of which has specific rules, or syntax, governing its use.

10. Components of a computer
Six primary components of the computer are
Input devices
Processor (control unit and arithmetic/logic unit)
Memory
Output devices
Storage devices
Communication devices
The processor, memory, and storage devices are inside the system unit.

11. Input Devices
An input device is an hardware component that allows you to enter data, programs, commands and so on in to a computer
Different types of input devices are designed to transmit different types of data or to transmit data in different ways.
The two primary input devices used are the keyboard and the mouse

12. Keyboard
Keyboard contains keys you press to enter data into the computer
A desktop computer keyboard typically has 101 to 105 keys

13. Mouse
The mouse is called a pointing device because it controls the movement of a pointer, or mouse pointer, on the computer screen and make selections from the screen.
The mouse either use optical sensor or ball that detects the movement of the mouse

14. Processor Also called Central Processing Unit
It has two units: Control Unit and Arithmetic logic unit.
The control unit interprets the instructions
The arithmetic logic unit (ALU) performs logical and arithmetic operations.
Example: Celeron, Athlon XP, Pentium processors

15. Memory Also known as RAM (Random Access Memory) It stores
Instructions
Data
Results (information)
Amount of memory in computers typically is measured in kilobytes or megabytes

16. Output Devices Display the processed information
Example: Printer, Display device
Two types of printer
Impact
Nonimpact

17. Impact and non impact printer
Impact printer prints by striking an inked ribbon against the paper
Dot matrix printer
Non impact printers form characters by means other than striking a ribbon against paper
Laser printers
Ink-jet printers

18. Advantages of Non impact printers
It can print higher quality text and graphics than an impact printer
It also do better job printing different fonts

19. Display Devices
A monitor is a display device that display the processed output.
Two basic types of monitor
CRT (cathode ray tube)
LCD (liquid crystal display)
CRT is the most common display device used with desktop computers
LCD also called flat panel monitor uses a liquid display crystal, similar to digital watch, to produce images on the screen
Monitor is composed of individual picture elements called pixels

20. Byte or Memory location
1 byte = 8 bits
1KB = about 1,000 bytes, (1024 or 2^10)
1MB = about 1,000,000 (one million) bytes, (1,048,576 or 2^20)
1GB= about 1,000,000,000 (one billion) bytes (1,073,741,824 or 2^30)

21. Storage Devices
Storage devices are used to store instructions, data, and information when they are not being used in memory
Six common types of storage devices are
floppy disks
zip disks
hard disk
optical discs
tape
Miniature storage media

22. Floppy Disks Floppy disk is a portable storage medium
It consists of a thin, circular, flexible plastic disk with a magnetic coating enclosed in a square-shaped plastic shell
A floppy disk drive is a device that can read from and write to a floppy disk
Formatting is the process of preparing a disk for reading and writing by organizing the disk into storage locations called track and sectors

23. Zip Disks Portable magnetic media
Hold about 500 times more than a standard floppy disk
Used to back up important data and information

24. Hard Disk
A hard disk consists of one or more rigid metal platters coated with a metal oxide material that allows data to be recorded magnetically
personal computer hard disks usually are fixed (i.e., not removable),
some portable computers have removable hard disk drives

25. Optical disc Uses laser technology for recording
Two types of optical discs are CD (compact disc) and DVD (digital video disc)
CDs are available in a variety of formats
CD-ROM
CD-R
CD-RW

26. Optical disc DVDs are available in the following formats DVD-ROM
DVD-RW

27. TAPE
Capable of storing large amounts of data and information at a low cost
Primarily used for long-term storage and backup

28. Miniature Storage Media
Rewritable media usually in the form of a flash memory card
It is the primary storage media used with digital cameras, music players, PDAs and so on

29. Communication Devices
Helps a computer to send and receive data, instructions, and information to and from one or more computers
Communication occur over transmission media, such as cables, telephone lines, satellites

30. Computer software Can be categorized in to two types
System software
Application software
System software is a program that controls the operations of computer equipment
Operating system is a part of system software
Application software consists of program that tell a computer how to produce information
Example: Word Processing, Spredsheet, database, presentation graphics

31. Networks
A network is a collection of computers and devices connected through the communication media such as cables, telephone lines, modems or other means
Local area network
Wide area network

32. Internet & Intranets Worlds largest network
Links millions of computers by means of cables, telephone lines and other communication devices
Users connect to the Internet either through an internet service provider or through an online service provider
Intranet is a special type of web that is available only to the users of a particular type of computer network, such as a network used within a company or organization for internal communication.

33. World Wide Web Contains billions of document called web pages
Web site is a collection of web pages
Web browser helps to access and view web pages
Each web page has a unique address called URL (Uniform Resource Locator)
URL consists of a protocol, domain name, and sometimes the path to a specific web page.
Web server is a computer that delivers requested web pages

34. World Wide Web
The first web page in the web site is called the home page
A hyperlink is colored or underlined text or a graphic that, when clicked, connects to another web page
Microsoft Internet Explorer is a widely used browser

35. Electronic Commerce Conducting business activities online
Three types of e- commerce
Business to Consumer (B2C) Business selling goods/products to the general public
Consumer to Consumer (C2C) Consumer selling directly to another consumer
Business to Business (B2B) Business provides goods and services to other businesses