components of computer system, Slides of Information Technology

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COMPUTER SYSTEM

Input

• (^) Input is whatever goes into the computer. Input can take a variety of forms; from commands you enter by keyboard to data from another computer (via a network connection) or device (via direct or network connection). A device that feeds data into a computer, such as a keyboard or mouse, is called an input device.

Output

• (^) Output is any information (data) that comes out of a computer. Output devices can be other computers, display screens, speakers, and printers.

Storage

Computer data storage is referred to as storage or memory, which can save digital data. Examples are RAM, hard disks, CDs, DVDs and removable flash memory sticks. Permanent, or non-volatile, storage devices do not require power to remember the data stored. Mass storage devices, like your hard disk, are non-volatile; a loss of power does not affect their ability to retain data. This category also includes ROM (Read Only Memory).

COMPONENTS OF COMPUTER SYSTEMS

• (^) Computer hardware - Are physical parts/ intangible parts of a computer. eg Input devices, output devices, central processing unit and storage devices
• (^) Computer software - also known as programs or applications. They are classified into two classes namely - system software and application software
• (^) Liveware/Peopleware - is the computer user. Also kwon as orgware or the humanware. The user commands the computer system to execute on instructions.

COMPUTER SOFTWARE

Software is a set of programs, which is designed to perform a well-defined function. A program is a sequence of instructions written to solve a particular problem. There are two types of software  System Software  Application Software

Virus and the Internet

• (^) A computer virus is a program or piece of code that is loaded onto your computer without your knowledge and runs against your wishes. Viruses can also replicate themselves. All computer viruses are man-made. A simple virus that can make a copy of itself over and over again is relatively easy to produce. Even such a simple virus is dangerous because it will quickly use all available memory and bring the system to a halt. An even more dangerous type of virus is one capable of transmitting itself across networks and bypassing security systems.

Viruses

• (^) A virus is a small piece of software that piggybacks on real programs. Example, a virus might attach itself to a program such as a spreadsheet program. Each time the spreadsheet program runs, the virus runs, too, and it has the chance to reproduce (by attaching to other programs) or wreak havoc.

Trojan horses

• (^) A Trojan horse is simply a computer program. The program claims to do one thing (it may claim to be a game) but instead does damage when you run it (it may erase your hard disk). Trojan horses have no way to replicate automatically.

Worms

• (^) A worm is a small piece of software that uses computer networks and security holes to replicate itself. A copy of the worm scans the network for another machine that has a specific security hole. It copies itself to the new machine using the security hole, and then starts replicating from there, as well.