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3.2 Looking into the 'means of conveying a message'

The diagram in Figure 6 shows that, for communication to take place, there needs to be some means of conveying the message between the sender and the recipient. I am now going to look at the essential components of 'means of conveying a message'. In other words, I shall treat 'means of conveying a message' as a system and look at
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Introduction

This course will help you understand how arguments are constructed and used in the Social Sciences. The material is primarily an audio file, originally 30 minutes in length and recorded in 1998.

This OpenLearn course provides a sample of Level 1 study in Sociology.


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1.6.2 Different types of sound

Sounds come in four categories.

  • Sound effects. Many UIs contain a range of warning beeps and reassuring sounds confirming that operations have been completed. These can include naturalistic sounds, such as the sound of a piece of screwed-up paper dropping into a waste paper basket.

  • Music. Many composers use computer systems to compose music, and programs such as games make extensive use of music. Short sequences of musical
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1.6.1 The role of sound

The use of sound is becoming increasingly common, particularly for the following types of application.

  • Applications where the eyes and attention are required away from the screen. Relevant examples include flight decks, medical applications, industrial machinery and transport. If you are a runner, you may have a heart rate monitor that allows you to monitor how fast your heart is beating. This is often indicated by an auditory beep, which speeds
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Acknowledgements

Except for third party materials and otherwise stated (see terms and conditions), this content is made available under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 Licence

Figure 1 ENIAC Computer. Photo © Science Photo Library

Rozin, D. ‘Wooden Mirror’,
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7.3 Using flowcharts to describe a task

Application programs are designed to perform specific tasks. These tasks range from the relatively simple to the extremely complex. In this section you will look at what is involved in planning a program to perform some simple tasks.

In order to write a program, the task the program will perform has to be first written as a list of actions. The actions have to be given in an order that will ensure the task is carried out successfully.

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6 A look to the future

So what will computers do for you next? Perhaps they will be the key to solving transport problems. Driverless cars, controlled by computers, are under development. If these ever come to fruition perhaps they could help to reduce the number of road traffic accidents by automatically reducing their speed when they come too close to another car. Or perhaps journeys could be made faster and less frustrating because cars will use communicating computers to analyse traffic density and move along t
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5.2 Electronic kitchen scales

A set of electronic kitchen scales is shown in Figure 7. Their basic operation is relatively simple. When they are switched on and, for example, a 500-gram object is placed in the scalepan, the display shows the digits 500 and the letter g.

3.2 What does a processor look like?

So what do these devices that are manufactured in such vast quantities look like? Processors are manufactured as integrated circuits. Essentially they are circuits, around the size of a fingernail, which contain many millions of electronic components manufactured as one very complex circuit. Figure 4(a) shows how a processor manufactured as an integrated circuit is packaged so it can be used as a component in an electronic circuit. The pins of the package are connected to the integrated circu
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2.4 Computer systems (contd)

As I have already mentioned, the functional blocks shown in Figure 3 relate very closely to, even though they are not necessarily identical with, the computer's physical components. The computer's physical components are normally known collectively as the hardware. Software is a term often used to refer to a
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Further reading

There is not a lot published on distributed development paradigms. The book by Coulouris et al. [2] indirectly introduces some of the paradigms introduced in this course. Lynch's book [3] on distributed algorithms is full of algorithms which are message passing based. The book by Patzer and 14 others [4] is a good practical introduction to many of the technologies detailed in this course. One of the few current books on JavaSpaces has been writt
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References

[1] E. Freeman, S. Hupfer and A.K. Arnald, JavaSpaces Principles, Patterns and Practice. Reading, MA: Addison-Wesley, 1999.
[2] G. Coulouris, J. Dollimore and T. Kindberg, Distributed Systems Concepts and Design. Harlow: Addison-Wesley, 2001.
[3] N. Lynch, Distributed Algorithms. New York: Morgan Kauffman, 1996.
[4
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Keep on learning

Study another free course

There are more than 800 courses on OpenLearn for you to
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Conclusion

This free course provided an introduction to studying Computing and ICT. It took you through a series of exercises designed to develop your approach to study and learning at a distance and helped to improve your confidence as an independent learner. 


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5.1 Introduction

The final approach to developing distributed systems is based on a radical view of such systems. The approach is based on work carried out by two American academics, Nicolas Carriero and David Gelerntner. These two academics developed a language known as Linda in the 1980s. The language, and its associated technology, has always been thought of highly by other academics within the distributed systems area, but has never taken off in terms of commercial use. However, in the late 1990s Sun deve
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4.1 Introduction

Many of you will already be familiar with event processing if you have developed visual interfaces with the later versions of Java. Developing such an interface consists of a number of steps:

  • A visual object such as a button is placed in a container such as an applet or a
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2.3 Synchronous and asynchronous message passing

Synchronous message passing involves one entity (usually a client) in the message passing process sending a message and a second entity (usually a server) receiving it, carrying out some processing and then sending back some response which the first entity processes in some way. While the second entity is carrying out the processing the first entity pauses waiting for the response.

In asynchronous message passing each entity in the process does not have to wait for the next part
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Learning outcomes

After studying this course, you should be able to:

  • describe some of the architectural and programming paradigms used in distributed system development

  • describe message passing and the role of protocols within a message passing paradigm

  • introduce the concept of a distributed object

  • describe how event-based architectures are used within distributed system development

  • introduce one implementation of an event-based architec
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Acknowledgements

The following material is Proprietary (not subject to Creative Commons) and used under licence (see terms and conditions).

Grateful acknowledgement is made to the following for permission to reproduce material:

Course image: Seika in Flickr made available under Creative Comm
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References

Brown, M. and J. Honeycutt (1998) Using HTML 4. Indianapolis, IN: QUE.
Choi, S., D.O. Stahl and A.B. Whinstone (1997) The Economics of Electronic Commerce. Indianapolis, IN: Macmillan.
Coulouris, G., J. Dollimore and T. Kindberg (2001) Distributed Systems Concepts and Design. Harlow: Addison-Wesley.
Gamma, E., R. H
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