N5 Computer Practice Theory

Concepts of Information and Communication Technology (ICT): Theory Downloaded from hlayiso.com

Basic Concepts: Types of Computers  Mainframe Computers  Servers  Personal Computers Downloaded from hlayiso.com

Types of Computers: Mainframe Computers  These type of computers have become commonly known as business servers as major organisations such as banks, government departments and supermarket chains use them to handle large amount of information.  They are room-sized computers that work at high speed and have very large storage capacities.  The cost of installing, running and maintaining mainframe computers are very high Downloaded from hlayiso.com

Types of Computers: Servers  Servers are a type of computer that stores and retrieves large amount of information. Different types of servers are used to handle different types of information.  Examples (web server, file server and database servers) Downloaded from hlayiso.com

Types of Computers: Personal Computers  Desktop Computers  Laptops Computers  Tablets PCs  Hand-held devices Downloaded from hlayiso.com

Desktop Computers This is the common type of personal computer . Is called desktop because it fits on a desk and is not portable. PC are manufactured under different names throughout the world but they can run the same programs and applications. Downloaded from hlayiso.com

Laptops Computers This kind of computer is also called notebook. They are small and portable computers that can be carried around and used. Most modern laptops can be connected to a standard monitor and keyboard Downloaded from hlayiso.com

Tablets PCs  Tablets are A4-sized computers that have no keyboard and run a modified vision of full computer operating software, often with extension to enable handwriting recognition.  The main function of Tablets PCs is to conduct light business function, note –taking, e-books reading and to provide wireless internet access. Downloaded from hlayiso.com

Hand-held devices  Hand-held are range of computers that are portable and can easily fit in a hand.  They include personal digital assistants, mobile phones/ smartphones and palmtop computers Downloaded from hlayiso.com

Memory and storage: types of memory  Random Access Memory (RAM)  Read Only Memory (ROM) Downloaded from hlayiso.com

Random Access Memory (RAM)  This is main working memory of the computer.  RAM is measured in megabytes, so computer could be said to have 512 MB of RAM  RAM is empty when the computer is first switched on.  RAM is a temporary memory of the computer because the information stored in RAM is lost if the power supply is turned off. Downloaded from hlayiso.com

Read Only Memory (ROM)  ROM is stored on memory chips.  Data is permanently burned into these chips.  The information and instructions held in ROM are there before the computer is switched on and still there when the power is off. Downloaded from hlayiso.com

How computer storage is measured  A computer must be able to ‘remember’ the information it is working with. The information is ‘remembered’ by being stored, either temporarily or permanently.  The capacity of computer memories and storage devices is indicated in Kilobytes (KB), Megabytes (MB) or gigabytes (GB) Number of bytes Storage term 1 kilobyte (KB) 1 024 byte 1 megabyte (MB) 1 024 000 byte 1 gigabytes (GB) 1 024 000 000 byte 1 terabyte (TB) 1 024 000 000 000 byte Downloaded from hlayiso.com

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