There are few categories of computers : - Personal computers, Mobile computers and devices, Game consoles, Servers, Mainframes, Supercomputers and Embedded computers.

• Personal Computers - can perform all of its output, processing, input, and storage activities. Two popular architectures are the PC and the Apple

• Mobile Computer - can carry to anywhere. Examples include notebook computers, laptop computers, netbooks, ultra-thins, and Table PCs.
  
• Mobile Device - the size of your hand. Examples are smart phones, PDAs, ebook readers, handheld computers, portable media players, and digital cameras.
  
• Game Consoles - is a mobile computing device designed for multiplayer or single player video games.
  
• Servers - a server controls access to the hardware, software, and other resources on a network. (Provides a centralized storage area for programs, data, and information)
  
• Mainframes - a very large, expensive, powerful computer that can handle hundreds and thousands of connected users simultaneously.
  
• Supercomputers - the fastest, most powerful computer. They are capable of processing more than one quadrillion instructions in a single second.
  

Embedded Computers - is a system with a dedicated function within a larger mechanical or electrical system, often with real time computing constraints.

Examples of Computer Usage : - Home User, Small office/Home office user, Mobile user, Power user, and Enterprise user.

• Home User - Communications, Entertainment, Web Access
• Small Office - Look up information, Send and receive e-mail messages, Make telephone calls
• Mobile User - Watch movies, Listen to music, Play video games, Transfer information
• Power User - Work with multimedia, Use industry-specific software
• Enterprise User - Communicate among employees, Blog

Computer Applications in Society : -  Education, Finance, Government, Health Care, Science, Publishing, Travel, Manufacturing.

Chapter 1 : Basic Introduction to Computer

Computer is an electronic device, operating control instructions stored in its memory.

The components of a computer

• Input : Scanner, Web Cam, Mouse, Microphone, Keyboard
• Output : Printer, Speakers, Monitor, 
• Storage : Optical Disc Drive, Hard Disk Drive, USB Flash, Memory Card, Memory Card Reader, External Hard Disk

The system unit known as CPU can be part as processor, memory and storage devices. The Modem is is one kind of a communication device.

Advantages of using computers
-Speed
-Reliability
-Consistency
-Storage
-Communications

Disadvantages of using computers
-Health Risks (expose too much radioactive)
-Violation of Privacy (Facebook)
-Public Safety
-Impact of Labor Force (less human working, more rely on devices)
-Impact on Environment

Green computing - reducing the electricity consumed, environmental waste generated when using a computer.
Strategies for green computing : - Recycling, Regulating manufacturing processes, Extending the life of computers,  Immediate donate properly or disposing of replaced computers.

Network and Internet is a worldwide collection of networks and data. People use internet to Communicate, Research and Access Information, Shopping, Banking, Online Trading, Entertainment, Download videos, Web application.

Computer Software - Installing : to set up a a software to work with the computer, printer, and other hardware.