Introduction

computer Computers are information processing machines used in different departments and organizations. They can be connected all over the world. Therefore, more productivity and good quality with less cost and legal constrains

Computers perform three main operations: Receive input(data raw facts) Process it according to predefined instructions Produce out output (information which is meaningful data).

Computer system The components of computer system are:- Hardware: Physical components like Screen, Cables, keyboard, system box and printer. The hardware cannot do any thing without software. Software: A set of instructions that tell computer what to do and how to do it. Such as: word processing, computer Games and Graphics Programs. Software is a collection of programs, data, and in formation. A program is a set of sequence instructions that tell the computer what to do. Hardware built on physical equipment but software (logical component) is built on thinking, knowledge and planning. A programmer is the person who makes the program using one of the computer's programming languages. Users : A person who use the software on the computer to do some task.

Computer Software There are tow kinds of software : system software application software

system software : it is the software which used by the computer or operators computer system such as operating systems operating systems : the most important system software. It is holds all instructions that make computer; displaying on the monitor; using the keyboard; saving and loading files; using secondary memory, managing Application software by being an interface between them and computer's equipment. Usually an O.S is supplied with the computer on hard disk, and it is loading into computer memory automatically when the computer is switched on. Some times you have to in put some information to configure your computer like adding printer

functions of operating systems booting up user interface task and resources management monitoring files management system security

application software It is the software used by users like word processors, Spreadsheets, databases, graphics and drawing programs, presentation tools

interface It is the way that user used to deal with the computer or communication his commands to the computer command line interface: Commands had to be typed on a keyboard as a line of text. It is slow process, and required a high degree of computer knowledge.

Graphic user interface (GUI): Uses pictures; windows; menus; and Icons to represent to objects and commands. The users can select his needs by pointing the mouse at and then clicking on it.

System development Involves the design, development, and the implementation of computer operations to replaced or update some process within the organization

Steps of system development Define requirements: under stand the business problem or opportunity Assess feasibility : to determine whether a new or improved information system is feasible solution System analysis : Analyze the information needs of end users, the organizational environment and any system presently used Product development for the hardware, software, people and data resources, and the information products that will satisfy the functional requirements of the proposed system.

Testing : test the system Training : train people to operate and use it Hand over to the client. Monitoring and maintaining the system: use a post implementation review process to monitor, evaluate, and modify the system as needed.

Information technology (IT) A set tools that are used to : receive, process, store retrieve, print and transmit in formation in an electronic form through computers these form can be: text, sound, picture or video.

Different between computer and people Computer are good for repetitive tasks, and for those tasks that require high speed. Accuracy and calculations. They are good for combining, storing, and retrieving data. People are good in tasks that require creativity and imagination where instructions cannot written. They are better for non-repetitive tasks, as well as, for tasks that need feelings

The computer versus people debate has developed into the context of information and communications technology being an integral part everyday life. The European commission posted some questions. The considered opinion was that computer literacy skill have becomes as important as traditional skills of reading, writing and arithmetic. It enables people to take advantage of the opportunities in work, as well as to practice fully in all other aspect of life.

Computer use Computer play an important role in societies. They are used indifferent fields as we mentioned. Computer use leads to:-

The eliminate repetitive tasks Providing greater efficiency and reliability in processing of information Providing a new employment opportunities Getting a large a mount of information from the internet in your home.

Doing your task quickly and easily from the home like making reservations, buying and purchasing via internet and sending messages via Working from home by use telecommunications Firms, which can sell directly to people in their home. There is not any need for renting stores.

Teleconferencing and video conferencing. The rapid development in machines and equipment. The standards of living, which are changed to higher level.

Computers at work Many different types of computer system are used according the type of business. Usually the computers are with high specifications for processing data. They are linked to make a net work. Other peripherals used are: the scanner, touch screens, bar code readers and the modem and internet server. The software, which is used, is word process, spreadsheet, databases, graphics programs, presentation programs, and communications programs, accounting and finance packages, statistics packages, a calendar program, decision support systems and project management, and other tools

Computer in education Computers are used in universities, collage, training, research and administration. Usually the hardware is a network or standalone computers with special tools. For administrations the software is word process, database and programs, training programs, word process, spreadsheet, desktop publishing programs finance packages. For class room use, there are educational packages, multimedia authoring, internet and and presentation and graphics packages.

security involves not only the physical security of computer equipment, but also the security of the data contained on the storage media

security the computer should be protected from damage (hardware and software) data should be backed up and protected from viruses passwords must be used for hardware and software back-ups are essential

Backups They are copies of all software files and information when you have in your computer system; use it when the original copies are damage because of physical failure use errors; accidents, or carelessness Backups can be made by different methods:

in all cases: copying onto floppies or external hard disk or magnetic tapes copying onto remote servers copying a hardcopy

in all cases 1. backup must be made on regular basis. 2. the user can use back-up programs that make the operation automatic in special times 3. keeping back-ups in a secure and safe place 4. make different copies and keep them different locations 5. label each floppy. 6. disks should be write protected

Security systems Security system of safeguards for protecting information technology against disasters, system failure, or unauthorized access that can result in damage or loss.

To protect your system you need to: 1. use authentication techniques 2. use authorization process. 3. use several and decryption codes 4. change the pass words frequently 5. make backup of files 6. save storage media in a save place 7. use anti-viruses programs

Power Cuts if there is power cut while the computer is on unsaved information will be lost files and equipment may be corrupted

To Minimized the damaged that can be caused because of power cuts the computer should be turned off and unplugged until the power is restored use surge protectors which protect your computer from surge, it may damage your system when power is cut or restored

use an uninterrupted power supply( UPS) that will keep the computer running for a littlie period, so you can save your computer and shut-down your computer properly

Protecting from viruses It is important to keep anti-virus software up-to-date. If there is not any up-to-date anti-viruses software installed into your computer, then you should following these guidelines:

1. do not use floppies from unreliable sources 2. use only registered software 3. never open an attachment unless it is from reliable source. 4. keep regular back-ups.

Licensing When you buy software you purchases a license to use it not for copyright. There is a license agreement that written on the package carton or in with the software itself There are two types of license

types of license Single User :the purchases can install the software into only one computer Site license: the purchases can install the software into multiple computers the number of which is specified by license agreement