The term "Human-Computer Interaction (HCL)" is commonly changing to terms such as "Man-Machine Interaction (MMI)", "Computer and Human Interaction (CHI)" and "Human-Machine interaction (HMI)".

Human-Computer Interaction is defined in many ways but Booth (1989) defines Human-Computer Interaction as "it is the study of the interaction between humans and computers".

Human-computer interaction is concerned with how current input and output technologies affect interaction and in what situation these technologies and techniques might be put to best use.

The common input devices include alphanumeric keyboards, cursor keys, mice, tracker balls, joysticks, graphics tablets, light pens and touch screen. Less common forms of input include moles or foot mice and even devices that detect eye movement.

Human-computer interaction is also concerned with hardware and software, to some this might be the most important in Human-Computer Interaction development. The number of input devices is continuing to expand, and many of the new devices are finding important role with different type of task. Some devices are so successful that some users say that they can not manage without them, for example a mouse, and some are not that successful.

According to Jenny Preece (1994), the goals of Human-Computer Interaction are to produce a usable and safe system, as well as functional system. Preece (1994) has also argued that these goals can be summarized as 'to develop or improve the safety, utility, effectiveness, efficiency, and usability of system that include computers'

Booth (1989) has argued that the usability of Human-Computer Interaction to be good, the system must be effectiveness, learnability, flexibility and user attitude.

Effectiveness -user must be able to use the system within a certain time.

Learnability - the user must be able to learn to learn the system in certain amount of training.

Flexibility - allowing adaptation to some specified percentage in task/environment.

Attitude - the system must be able to accept the level in human cost in terms of tiredness, discomfort, frustration, and personal effort.

The importance of Human-Computer Interaction can be shown by the benefits in cash terms that it has brought. A large percentage of the design and programming effort of projects go into the user interface. The human-computer interface is a fundamental part of making the product more successful, safe, useful and pleasurable to the user.

The tools and techniques that have been developed in this field have contributed immensely towards decreasing costs and increasing productivity. Savings were attributed to decreased task time, fewer errors, greatly reduced user disruption, reduced burden on support staff, elimination of training, and avoidance of changes in software after release. In the past few years, evidence have shown that estimating all the costs associated with usability engineering, that the benefits can be up to 5000 times the cost.

There are also other the benefits in terms of productivity, individuals have the benefit to install software by their own and the help of the wizard, for example Microsoft office. Organisations will also benefit from this, for example changing job content, satisfaction, working environment, power and influence

Safety is also one of the major benefits in Human-Computer Interaction, places like nuclear plants, flight control will benefit from Human-Computer Interaction, because Human-Computer Interaction improves the safety and the usability of a system.

Booth (1989) has suggested that other disciplines roles that Human-Computer Interaction plays are Software engineering, Computational Linguistics, Artificial Intelligence, Cognitive Science, Sociology, Ergonomics, Organizational Psychology, Mathematics, Cognitive Psychology and Social Psychology.

Ergonomics - is the study and design of the physical characteristics of computer workstations. Discipline of ergonomics has a great experience of the design of automobiles and aircraft, which can be applied in Human-Computer Interaction.

Software Engineering - its role in the in the control and management of the design and development process. Also providing new tools to improve the interaction between human and computer.

Mathematics - mathematical formalisms are now being applied to human-computer interface as by which logical inconsistencies can be exposed.

Cognitive Psychology - is the study of human information and behaviour within HCI (human mind and the errors we make). It is a great use in Human-Computer Interaction because Cognitive Psychology offers the knowledge of how to avoid problems.

Artificial Intelligence - gives Human-Computer Interaction the possibility of intelligent system and offers variety of cognitive models for representing the user.

Computational Linguistics - gives Human-Computer Interaction better understanding of the dialogue that occurs at the human-computer interface and the possibility of the natural language systems.

Cognitive Science - Booth (1989) has argued that Cognitive Science offers Human-Computer Interaction more interpretative approach to examining the role of knowledge, meaning and understanding within human-computer interaction.

Social Psychology -better understanding of the social aspects of both the system design and implementation within the Human-Computer Interaction.

Organizational Psychology - gives Human-Computer Interaction the knowledge of businesses and institutions, which can be used to understand the impact of computer system in these organizations. Provides techniques that can help to identify problems, which are created when computers are introduced in a working environment.

Sociology - study of issue such as user's social class, gender and education in determining the acceptance of the user within a system.

Booth (1989) has suggested that the future of Human-Computer Interaction will contain high-resolution display, with icons and windows. Workstation will be will have voice annotation, mostly notably for voice input and output. The number of input devices will increase near future, which will mean that choosing devices to perform a particular task is likely to become worse.

Reference:

John M. Carroll (2002), "Human-Computer Interaction in the new millennium", New York, ACM Press Addison-Wesley.

H.T Smith and T.R.G Green (1980), "Human Interaction with computers", London, Academic Press.

Booth, Paul A (1989), "An introduction to human-computer interaction", Manchester, Hove: Erlbaum.

Jenny Preece...et al. (1994), "Human-Computer Interaction", Wokingham, Addison-Wesley.

Jenny Preece and Laurie Keeler (1990), "Human-Computer Interaction", Hemel Hempstead, Prentice Hall in association with The Open University.

Georgila K., Sgarba K., Tsopanoglou... et al., International Journal of speech Technology, Vol 6, No. 2, P.P 145-159, April 2003.

Myers B.A (1996), "A brief history of Human Computer Interaction Technology", Available at this website: http://www-2.cs.cmu.edu/~amulet/papers/vihistory.tr.html (accessed 10/11/2003).