Author: mety Nagm Labels:: , ,

The operating system

is a special type of program which loads automatically when you start your computer. The operating system allows you to use the advanced features of a modern computer without having to learn all the details of how the hardware works. There are a number of different types of operating system in common use. The IBM PC (Personal Computer) was introduced way back in 1981 and was originally supplied with an operating system called DOS (Disk Operating System). This operating system was very basic, and you had to be a bit of a computer expert just to understand how to use it. It was NOT user-friendly. Later on, Microsoft introduced Windows and this is the operating system which is most widely used on PCs today.

• To complicate matters further, there are a number of different types of Windows. The first widely used version of Windows was called Windows 3.1. This was more powerful than DOS and far easier to use. It had a Graphical User Interface (GUI), i.e. you could 'drive' it using a mouse and drop down menus. Later, different releases of Windows were introduced. The good news is that later versions of Microsoft Windows look almost identical to each other and are all much easier to use than Windows 3.1.

• IBM produced an operating system called OS/2 but this was largely ignored and is only used by a few companies.

• UNIX and Linux are other examples of operating systems which may be run on PCs.

• Other types of computers, such as those manufactured by Apple have a completely different operating system.

A Graphical User Interface (GUI)

It is simply an additional part of the operating system which displays windows and drop down menus, and also enables you to drive your computer using a mouse. Examples of operating system which use a GUI include Windows the original version of DOS there are no menus, no icons and nothing for the mouse to click on. You had to know a special language which you then typed into the computer to make it do anything The advantages of using a GUI (Graphical User Interface)

• All programs look similar and when you switch from a program supplied by one manufacturer to a different program supplied by another manufacturer, you will find the transition very easy.

• Application programs work in the same way as the underlying operating system, and also look very similar, which means that they are easier to learn and use.

• The GUI also allows programmers to easily write consistent looking programs

An application program is the type of program which you use once the operating system has been loaded into memory (RAM). Examples include word processing programs (for producing letters, memos etc), spreadsheets (for doing accounts and working with numbers), databases (for organising large amounts of information), games and graphics programs (for producing pictures, advertisements, manuals etc)

Systems development

The way new software is specified, written by programmers, tested and then delivered to the user

Systems development cycle

• Most IT projects work in cycles. First, the needs of the computer users must be analyzed. This task is often performed by a professional called a 'Systems Analysts' who will ask the users exactly what they would like the system to do, and then draw up plans on how this can be implemented on a real, computer based, system.

• The programmer will take the specifications from the Systems Analyst and then convert the broad brushstrokes into actual computer programs. Ideally at this point there should be testing and input from the users so that what is produced by the programmers is actually what they asked for.

• Finally, there is the implementation process, during which all users are introduced to the new systems, which often involves an element of training.

• Once the users start using the new system, they will often suggest new improvements and the whole process are started all over again. These are methodologies for defining a systems development cycle and often you will see four key stages, as detailed below.

- Analysis

- Design

- Programming

- Testing



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I made these pages for me and my friends to help solving the problem we face regarding Computer & internet, if anyone wants me to answer a question or find out about some information please send me email and I will try to reply.*P.S. some of the article I wrote and the other I found on the internet I posted them in sprit of learning and shearing, please forgive me if you found something you don’t want to be in my blog, email me and I will delete them. Thank you for your interest in my pages.امل نجم Amal Nagm

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