2 What is software?Software is the name given to all the programs that run on computer hardware.There are two main types of software:Operating software (also known as systems software)Applications software
3 Operating systemsAn operating system is a program that controls the hardware.Operating systems perform the following tasks:They assist applications software to communicate with the hardware (e.g. allow a word processed document to be printed)They manage the system resources (e.g. allocate CPU time to the tasks being undertaken)
4 Operating systemsThey manage the transfer of data to and from the systems peripheral devices (e.g. keyboard, mouse, scanner, printer)They manage system security (e.g. allocating restricted rights to users to do certain things)
5 Operating systems Examples of operating systems include: Windows XP Windows Millennium EditionWindows 2000Windows NTUNIXOS/2
6 Operating systems Hardware The operating system acts a a ‘shell’ around the hardware. The applications software need an operating system to work, and users need the applications software to interact with the hardware via the operating system.ApplicationOperating systemUserHardwareApplicationApplicationUserUser
7 MultitaskingMultitasking is the ability to do more than one thing at a time.If an operating system can multitask, it enables a computer system to do several things at the same time (e.g. A user can print a document whilst reading their s).
8 MultiuserA multiuser facility allows more than one user to access data or an application program at the same time.Without a multiuser facility in an operating system it would be almost impossible for a network to function.
9 User interfacesThe way in which the user of a computer communicates with the machine is called the Human-Computer Interface or User Interface.This is an important function of an operating system.
10 User interfaces A good human-computer or user interface needs: To be user friendlyTo be attractive to useTo be effectiveTo be easy to use
11 User interfacesA user friendly interface should make it possible for the user to use the software without having to read the entire manual first!An interface that is attractive to use will encourage users to use the software.
12 User interfaces An effective interface will do its job efficiently. An easy to use interface will have menu structures that are consistent in design and layout across several different software packages (e.g. the fast save option will be in the same place on the toolbar and have the same icon).
13 User interfaces GUIs (also known as Icons). Toolbars. Drop-down menus. Pop-up menus.Combinations of the above.
14 Graphic User Interfaces Graphic user interfaces (also known as GUIs) are usually called ICONS.GUIs are small pictures that represent actions, and they can be selected by ‘clicking’ on them with the mouse.
15 GUIs or Icons that will activate particular programs Some examples of GUIsGUIs or Icons that will activate particular programsMicrosoft WordOutlook Express
16 Some examples of GUIs used with a toolbar GIUs or Icons that will activate particular tools on a ToolbarText JustificationPrintClipboardFast Save
17 Some examples of toolbars Microsoft WordMicrosoft ExcelMicrosoft AccessNote the use of GUIs or Icons that are common to all the toolbarsFast Save, Print, and Print PreviewExamples include:Help
18 Some examples of drop-down menus Note that options that are not available are ‘greyed’ or ‘ghosted’
19 Some examples of pop-up menus The Microsoft Windows ‘Start’ Menu pops up when the ‘Start’ button is pressedThe ‘AutoShapes’ Menu in Microsoft Word pops up when the ‘AutoShapes’ button is pressed
20 Other forms of interface All the examples shown so far have been ‘point and click’ device driven.There are, however, other forms of interface that are command and key driven.
21 An example of a command driven interface Before the introduction of GUIs by Apple Mac and Microsoft, computers had to be given commands in DOS. These were typed in, and often used abbreviations.This example is the command used to view the directory of all the programs and files in ‘Windows’.
22 An example of a key driven interface This example is taken from the Microsoft Word Toolbar.For example:Pressing the ‘Alt’ and ‘f’ keys at the same time selects the File option.Besides being able to select a command by clicking on the appropriate word with a mouse, these options can also be selected by the use of the keyboard.Pressing the ‘Alt’ and ‘o’ keys together at the same time selects the Format option.
23 Utility programsUtility programs are often included with the operating system although some – such as antivirus programs – often have to be purchased separately.Utility programs perform routine tasks that help the user to get the most out of the system.
24 Utility programs Tasks that utility programs perform include: Renaming filesListing filesDeleting and copying filesSending files to the printerSorting dataRepairing damaged filesBacking up files