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16.2 Processes at the checkout

From the point of view of the customer and the checkout operator, a supermarket's ICT system is like the stand-alone computer you saw in Figure 10 in Section 9. The system map in Author(s): The Open University

11.7 Applications

Most people buy computers in order to run applications. There are many different examples of software application, including word processors and spreadsheet, database and graphics packages. Some are combined together in 'office' suites, such as the StarOffice applications you can find on the Open University's Online Applications disk.

Word-processing software, such as Microsoft Word, allows you to create, edit and store documents. You can produce very professional-looking documen
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2.1 Introduction

In this section we will cover the following topics:

  • browsing for information on the Web;

  • searching for information on the Web;

  • using search engines;

  • bookmarking websites;

  • finding images on the Web;

  • how to reference sources.

Some of the material in this section has been drawn from Safari, an interactive website provided by the Open University Library. Safari cover
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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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Keep on learning

Study another free course

There are more than 800 courses on OpenLearn for you to
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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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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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2.4 The message passing idea

Figure 1 shows the central idea behind the message passing paradigm. It involves an architecture in which clients and servers communicate using communication lines. In this model, in contrast with the others that are to be presented in this course, the underlying structure of the network is visible via the communication media used to connect servers and clients and devices such as sockets, ports and server sockets which are involved in the transfer of a message from one computer to another.
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2.2 Fixed and adaptive protocols

The protocol described above for a simple naming service is an example of a fixed protocol. This is a protocol whose vocabulary is fixed: it is embedded in the client and server's code and data and does not change. An adaptive protocol is one where the protocol changes. A fixed protocol could change over a period of time because the functionality provided by a server changes. However, this change will be over months or years rather than over seconds.

There are some instances wher
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2.1 Protocols

Message passing is the simplest form of development paradigm. For example, the way that a client running a browser communicates with a web server is via message passing.

Message passing is based on the idea of a protocol: a language which embodies the functions required by one entity in a distributed system (usually a client) which another entity provides (usually a server). As an example of a protocol consider Table 1. It shows the protocol associated with a naming servic
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1 Distributed models

Before looking in detail at some of the technologies it is worth examining some of the implementation and design models that can be used for distributed system development ranging from the familiar, message passing, to the unfamiliar, tuple-based technology. In describing these I have two aims: first, to detail the variety of methods and architectures that are available and the degree of closeness they have to Internet technologies such as TCP/IP, for example message passing is close in conce
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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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5.2 The application

The first application I shall describe is that of an online bookseller. Such a book sales system would carry out a number of functions:

  • It would allow the user to browse through a catalogue of books.

  • It would allow the user to browse through a list of the most popular books, with the list being updated every hour.

  • It would provide the facility whereby a user can buy books and add them to a notional shopping basket.


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3.3 Email

This is one of the most ubiquitous technologies on the internet and, along with the World Wide Web, is the most used. When you write an email you use a program known as a mailer. When the email is completed it is sent via a number of computers known as email servers and via a number of other intermediate computers before it reaches its destination where it is read. In e-commerce applications email is a subsidiary, but important technology. It is used as the transport medium for
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2.5.5 Email providers

These are sites which provide free email facilities; often they provide other facilities such as sending anonymous mail and constructing mailing lists. Such sites are valuable to users who are too impecunious to be able to afford conventional mailing software and to frequent travellers who can access such sites anywhere in the world. Their main disadvantage is that they tend to be slow compared with conventional mailing utilities such as Microsoft Outlook and Eudora.


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2.5.2 Link checking sites

The World Wide Web contains millions of web pages. Many of these pages are impossible to read, even though many existing web pages will reference them: your browser will usually return with some message such as ‘Error 404 Page not Found’ when you try to access them. Error 404 is a standard message returned by web servers when a non-existent page is accessed. It is also the telephone area code for Atlanta in the United States; you will occasionally hear technical staff referring to non-exi
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2.2 E-tailing

The next example is probably the one that you expected me to introduce first: that of selling goods over the internet. However, I deliberately introduced supply chain management first since it is an area where companies are making huge savings in their investment in internet technology. The investments in retailing using the internet (e-tailing) are only gradually being realised.

The archetypal e-tailing application Amazon is renowned for the fact that it only sells books over th
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Teaching assistants: support in action (Chinese)
本免费课程是“助教:提供行动支持”课程的中文翻译版本,英文原版也在本网站中提供。 This free course is the Chinese version of Teaching assistants: support in action which is also available in English. First published on Tue, 16 Feb 2016 as Author(s): Creator not set

Understanding early years environments and children’s spaces
This free course, Understanding early years environments and children's spaces, considers some of the different environments children encounter in their early years. It encourages you to develop your reflection of children's environments and provides opportunities for you to investigate and evaluate young children's experiences and your role in supporting them.Author(s): Creator not set

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What children and young people say
This free course, What children and young people say, looks at how practitioners and other adults talk to children and young people, and considers how this influences what they tell us. It identifies how children and young people would prefer to be engaged with, what would encourage their confidence in authority figures, and outlines the ways in which adults can improve on their listening techniques.Author(s): Creator not set

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