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System software is the name given to the software that controls the hardware and how all other software works. The most commonly used system software, called an operating system, is Windows, made by the Microsoft Corporation. Without an operating system a computer just would not work.
Operating system • Popular operating systems include Windows XP, Windows NT, Windows 2000, Mac OS X, LINUX and UNIX.
Booting • The process of starting a computer is known as booting. The first thing a computer does when it is booted is to check that it is working properly. It does this by following certain instructions held on a ROM chip known as the BIOS.
You can often see this happening as various lines of text briefly appear on the computer monitor. It will then look for an operating system (OS) to tell it what to do next. The operating system is loaded from disk to the computer’s random access memory (RAM).
Software Control The operating system controls how all software applications, games or other programs work on the computer, such as: • file management — saving, copying, renaming and deleting files • multi-tasking — allowing more than one program to run (work) at the same time;
•for example, using a desktop publishing program while a graphics program is still running • multi-user — allowing more than one user on a computer network to access the same file at the same time • security — when passwords have been set, allowing only those with the correct password to use the computer.
Utility software • Utility software is specialized software that tries to protect and maintain the system software, just like a mechanic maintains the smooth working of a car’s engine when it is serviced. Examples of the tasks undertaken by utility software include protecting software against damage caused by computer viruses, making copies of files (backing up) and recovering files after software has stopped working (crashed).
Hardware control • The operating system also sets the rules for controlling hardware resources such as: • peripherals — controlling peripheral devices such as keyboards, printers and scanners • memory — controlling the amount of memory used • CPU — controlling the time allocated to a task by the central processing unit (CPU) • disk space — controlling the amount of disk space used.
QUESTIONS • 1 Explain what is meant by: a booting b operating system. • 2 Give four ways each in which an operating system controls hardware and software on a computer. • 3List three different operating systems used on computers.
Application software • Note: an operating system such as Windows is essential for a computer to work. • Most of the software we use regularly has been created to do specific tasks —for example, word processing or desktop publishing. The term for software such as this is application software or program. • Application software is defined as programs that enable the computer to carry out one or more specific tasks.
General-purpose software • The most popular application programs are those that are not specific to any organisation or business and can be used by anybody. • The programs that you use at school or home — word processing, databases, spreadsheets, presentation, drawing and painting — will be such programs.
These programs are known as general-purpose software, because the user decides what to use the software for. For example, you might want to use a word processor to write a letter or curriculum vitae (CV), or to design a poster for the school play.
General—purpose software is much cheaper because it has been used by millions of people over a number of years and is generally error (bug) free. Popular examples of application programs (software) are given NEXT.
Custom-written software • Custom-written software, which is also known as bespoke or tailor-made, can modify general-purpose software to perform specific tasks for the user.
Again word processing, spreadsheet and database programs are examples of general purpose software that can be custom-made by automating certain parts of the software, or writing and adding programming modules to perform specific tasks.
Specialised software • Specialised software is written solely for a specific task. • Examples are software used by air traffic controllers to manage the flights of thousands of aircraft, accounting software, airline reservations software and computer-aided design.
These are not general-purpose, since the users of these kinds of software (for example, accountants and engineers) are trained in a particular field of expertise. • Since this software is specific to an organisation or business it can be very costly to create.
Integrated software • Many computers are sold with integrated software already installed. • Integrated software is the term for a program that includes all the major types of application (for example, word processing, spreadsheet and database) and brings them together into a into single software package.
Microsoft Works is an example of integrated software. Some integrated software, such as AppleWorks, also includes presentation, drawing and painting features, making in effect six programs in one.
The large software companies such as Microsoft, Corel and Lotus, sell their main application programs together in one package. • Although packages such as these are sold as integrated software, it is not true integrated software, as all of the programs are still separate applications.
There are five advantages of integrated software 1. You get extremely good value for money, with up to six packages rolled into one. 2. You have to learn how to use only one package since the user interface is the same for choosing commands.
3.Data can be easily transferred from one integrated application to another, using cut, copy and paste. • It does not take up as much disk space as separate applications. • It takes up less memory than separate applications.
There are two disadvantages of integrated software 1.Not all of the features of single applications are included. Therefore, the integrated software may not be up to the task you want it for. 2. Some integrated packages do not include all of the applications that may be required.
NOTE • Choosing software should be no different from choosing any tool for a job. • Just as in construction you decide whether to use a screwdriver or hammer to do a particular task, so with software you need to decide what it is you actually need to produce. and then choose the most appropriate program. • This is very important when choosing programs to use for your coursework.
QUESTIONS • What is an application program? Give three example of application programs. • What is the difference between general purpose and custom-written software? • Give one advantage and one disadvantage of integrated software. • What application software would you use for: a lots of calculations b searching and sorting data c creating an invitation?
How you interact with a computer and use it is controlled by the computer—user interface. • After the computer has booted up and loaded the operating system, you will see the user interface • (also known as the human—computer interface).
There are three main types of user interface: 1.command-line interface 2.menu-driven interface 3. graphical user interface (GUI).
Command-line interfaces • Command-line interfaces require you to type in commands using a special language • This special language makes command line interfaces difficult to use, especially for new computer users. • One example of a command—line interface is the Microsoft Disk Operating System (MS-DOS).
In all cases, the command must be given at a specified prompt to indicate the drive on which the data is stored and the directory or folder in which the file is located. For example, a prompt which shows • C:\> means that all commands will be performed with data on drive C: • A command prompt with A:\> refers to a diskette in the disk drive. A sub-directory or folder is similar to a drawer in which related data items are held. Hence data may be stored in a folder such as C:\SBA> which is on the hard drive.
Menu-driven Interfaces • A menu is a list of options from which you can choose what you want to do. Application programs use menus as an easy alternative to having to learn program commands. • Menu-driven interfaces were developed to try to make the interface friendlier and easier to learn. You can control the computer by choosing commands and available options from a menu, using the keyboard or a mouse.
Graphical User Interfaces • Graphical user interfaces (GUIs) are provided by the Windows and Macintosh operating systems. • GUIs are presently regarded as the user interfaces which are easiest to use. As a result, all computers are now supplied with a GUI system installed, • The best way to remember what makes up a GUI is to think of the word WIMP, which stands for Windows, Icons, Menus and Pointers.
WINDOWS • A window is that part of the screen that holds its own document or message. • Most computers now use window-based programs. A window can take up the whole screen or can be resized, moved or shrunk (minimised).
Each time you open a folder, you see its contents in a new window More than one window can be open at the same time. • This is particularly useful if you want to move from one window to another or to copy files from one window to another.
Icons • An icon is a tiny picture of an object that is displayed on screen. Normally, you can use the icon in some way. • For example, by using the mouse to double click on the icon of the Microsoft Excel spreadsheet program, you will start the program.
Icons are designed to make things easier for computer users. Instead of having to remember commands, all you have to do is to remember what the icons look like. • Icons are not just for programs. There are icons for folders, the recycle bin (wastebasket), disk drives and printers.
Menus • An advantage of using menus in Windows or on a Macintosh is that, for most programs, the first few menus are always in the same order. • They also carry out the same functions, no matter which program you are using. • For example, the file menu is first and enables you, among other things, to create, save and print a document.
Pull-down means • Pull-down means(Fig 1.33) are activated by clicking on the menu item (such as ‘File’) using the left mouse button. • The menu pulls down just below the menu item, and you can scroll down through the various items. More complicated pull-down menus can produce additional pull-down or pop-up menus.
Pop-up menus • Pop-up menus are activated by clicking anywhere on the document screen using the right mouse button. • Some standard commands and options are available on these menus, including the cut, copy and paste commands.
