11 Human-Computer Interfaces (HCIs)
Find the following key words in this chapter and write your own definition of each in the boxes.Add more stems to this revision map to note down what you learn in this chapter.
11.1 Operating Systems
- Operating systems are programs which allow the hardware of a computer to work with the software application programs which are installed. Examples of operating systems are Microsoft Windows, Mac OS X and Linux.
- Below are some of the key features of operating systems:
- A user interface controls how a person interacts with a computer. There are different types.
- Modern operating systems use graphical user interfaces(GUIs).GUIs can be summarised by the word WIMP:
- Windows are used to carry out different tasks.
- Icons are pictures you can click to open different programs.
- Menus can be used to choose what you want to do.
- Pointers are cursors on the screen (a little arrow controlled by moving the mouse)
- GUIs also allow you to use office assistants where you can type a question to get help. You can also see demonstrations of software by viewing online tutorials.
- GUIs often allow you to customize your desktop by changing your wallpaper, changing icons, adding a colourful screen saver, or changing brightness settings.
- The advantages and disadvantages of graphical user interfaces are:
- Advantages– You do not need to remember complicated commands to type in – you can just use icons and menus to find your way around the system. You can use a mouse to control a pointer, which is easier than having to type everything in.
- Disadvantages– You need more memory and storage space to run a GUI in order to load and store all of the graphics. Computer experts who know advanced commands may find GUIs slower than command line interfaces.
- State four features of a GUI user interface. (4 marks)
- Explain what is meant by multitasking facilities. (2 marks)
11.2 Types of User Interface
- In addition to graphical user interfaces (GUIs), there are five other types of user interface:
Command Line / You need to remember and type in certain commands to operate. Computers normally allow you to use command line features when deleting all data from a PC and installing a new operating system. / Requires less memory/storage than GUI – no graphics to load. Quicker if an expert knows the commands which are needed. / Hard for beginners who do not know the different commands. If commands have any spelling errors, it will not work.
Menu / Dialogue Box / With menus, you have to select a choice from a list of different menu options. Dialogue boxes can also pop up on the screen to ask the user a question or inform them about something, e.g. when an error occurs with an application. / No need to remember commands like with command line interfaces. Easier for beginners than command line interfaces. / Too many levels of menus can be annoying for the user. It is not as intuitive/easy to use as graphical user interfaces.
Voice user interface (VUI) / You can give the computer verbal commands by speaking into a microphone. Used in some GUI operating systems which come with voice recognition software. / It is useful for people with disabilities who have difficulty using a normal mouse/keyboard. / Some voice interfaces struggle with different accents, difficult words and high levels of background noise.
Touch / You can use gestures to control a touch screen. Used in mobilephones, learningaids and point of sale systems with self-service checkouts. / Using gestures is intuitive and nearly everyone can use touch screens without training. / Some people will find it easier to type lots of data using a normal QWERTY keyboard.
Biometrics / Uses unique parts of the body to control a computer. You can log in to a computer using a retinal (eye) or fingerprint scan. Computers can catch criminals by looking at the way they walk or at their DNA print. / You do not have to remember a password when logging in with biometrics. Biometrics can also help to reduce crime. / Biometrics are expensive. People may worry about having personal details like fingerprints logged by a computer.
- Explain two advantages of a command line user interface. (4 marks)
- Give two forms of a biometric user interface. (2 marks)
11.1 Operating Systems / 34. One mark for each, up to maximum of four: windows; icons; menus; pointers; office assistants, online tutorials, customized desktop.
35. Running more than one application (1 mark) at the same time (1 mark).
11.2 Types of User Interface / 36. Quicker for experts (1 mark) who know what commands are needed (1 mark). Requires lessmemory/storage (1 mark) because no GUI graphics. (1 mark)
37. Any two of (1 mark each): retinal; DNA; fingerprint; walking.
Page 1of-1 / WJEC ICT Revision Guide Unit 3©ZigZag Education 2011