13.3 Optical storage

A CD-ROM (Compact Disk Read Only Memory) uses a laser-based optical form of storage. This type of disk has been used for many years to distribute music and computer software. A CD-ROM drive is needed to read the disks. Data is locked into the disk during manufacture, and cannot afterwards be changed.

There are two other types of CD device for computers: CD-R (CD-recordable) and CD-RW (CD-rewritable). With the right sort of CD drive in your computer, you can ‘burn’ data (that
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13.1 Introduction

I'll now introduce you to some different storage media and devices. As the uses for ICTs have expanded and developed, so has the need to store ever larger amounts of data. I've quoted some figures for storage capacity in this section but, given the rapid rate of development in ICT systems, some of these figures may be out of date when you read this unit.


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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 do
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11.6 Operating systems

A computer requires software just to look after itself and to manage all its components; this is called the operating system. The operating system handles communication with the other software on the computer and with the hardware resources of the machine, such as the processor and memory. The operating system provides a means of running the computer's application programs. It also provides a standard user interface with windows, buttons and menus so that users can interact with the co
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11.5 Programming languages

A computer program is written in a programming language and contains the instructions that tell the computer what to do. Developers write new software using specialised programming languages. The resulting programs (or ‘source code’) can be converted into the low-level instructions understood by the processor. There is a wide range of programming languages to suit different types of task; if you look at advertisements for programming jobs in newspapers or online you will get an ide
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11.4 Computer software

The electronic components and other equipment that make up your computer system are known as hardware. In order to make the computer do things, such as help you to produce your TMAs, edit photographs or draw diagrams, you also need computer programs, which are called software.


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7.2 Should I unsubscribe from mailing lists?

Many spam messages have a line at the bottom offering to unsubscribe you from a mailing list, but you should be very wary of doing this. Quite often the senders of the spam will use the ‘unsubscribe’ option to verify that your email address is live. They may then sell your address to other people for use in spamming. So using the unsubscribe option can increase your spam rather than reduce it. Our advice is never to use the unsubscribe option unless the mail you receive is from a well-kno
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7.3 Quality of customer service

This is probably the key determinant of customer satisfaction. Most online transactions go through flawlessly. But some don't. Goods fail to arrive, or are delayed, or delivered to the wrong address. Or what is delivered doesn't match what you ordered. With a real-world bricks-and-mortar retailer, the solution is obvious: you phone or turn up at their premises and speak to a human being. But what do you do if an online order goes wrong? Whom do you phone? And where is the number for customer
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1 Introducing eBay

One of the earliest popular applications of the Web was an online auction system called eBay. Think of it as an enormous car-boot sale. In an ordinary (offline) auction system, you brought things you wished to sell to an auctioneer who catalogued and then sold them on your behalf at a physical auction attended by people who placed bids for the goods. There would be a series of bids with the auctioneer encouraging people to bid against each other, thereby raising the selling price. The highest
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Acknowledgements

The content acknowledged below is Proprietary (see terms and conditions) and is used under licence.

Grateful acknowledgement is made to the following sources for permission to reproduce material within this unit.

Figures

Figure 6 NanoElectronics Japan

Figure 30 The Cottingley Fairies © Science and Society Picture Library

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7.2 Frameworks

A framework is a set of classes with well-defined interactions which are designed to solve specific problems. Frameworks are usually developed for a specific domain of application, say financial management or document preparation. They go some way towards a complete solution, but require some degree of customisation, usually through the creation of subclasses within the framework or by overriding operations. Coplien suggests:

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6.12 Self-assessment questions

SAQ 1 Actors

  • (a) Explain why the actors in a use case diagram do not represent actual individuals.

  • (b) Suggest a guideline that will help you decide whether or not to include
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6.11 Issues with use cases

There can be a tendency to make diagrams too complex. You can reduce the complexity of your use case diagram by:

  • redrawing it at a higher level of abstraction;

  • splitting it up into smaller modules, which the UML calls packages.

In the case of the hotel chain, we might partition our model into the following three packages:

  • reservations;

  • checking guests in and o
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6.2.1 Using a sales website

A visitor to a sales website is usually able to:

  • browse through the details of the goods for sale;

  • search for a particular product;

  • check on the availability of goods;

  • read reviews of the products by other purchasers;

  • register to receive newsletters which detail new items of interest;

  • buy products using credit or debit cards, and in some cases, other payment methods s
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3.4 What has any of this to do with computers?

Human beings invented computers because we have a compelling interest in data. We seek to turn our perceptions of sensations into symbols, and then to store, analyse, process, and turn these symbols into something else: information. Modern computers, with their enormous storage capacity and incredible processing power, are an ideal tool for doing this. They allow us to acquire data, code it in terms of signs, store, retrieve, or combine it with other data. Sophisticated o
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School Governors: Secondary school monitoring
School governors need to be involved in the monitoring and evaluation of secondary schools. But what areas should you be monitoring and how can you ensure that monitoring is effective. This unit will help you assess these matters and also look at the kind of evidence you should be sourcing, and how that evidence should be evaluated.Author(s): Creator not set

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Exploring childrens' learning
How does a child’s mind and behaviour change as they develop over time? In this unit four theories of child development are explored. Each theory views child development from a different perspective and all have underpinned psychological research for many years, and continue to do so today. By the end of this unit you will have a good understanding of each of the theories and will probably have begun to challenge your own assumptions about how your own children, or children you know, have deve
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Introducing observational approaches in research with children and young people
This unit introduces you to analysing academic writing and, in particular, the way an article might be structured to clearly explain an investigation to other researchers. It explores observation of children and young people using qualitative observation approaches in small-scale studies. First publishe
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3.11.2 Answering a question in exam conditions

Write out a few exam questions on pieces of card, shuffle them and then pick out a question at random and try to answer it in the time the exam allows. Doing this can give you a sense of the amount you can reasonably write in an exam. You should also get an idea of whether or not you are being too ambitious about what you can cover within the time constraints of an exam. You should be wary of overshooting the timeslot for an exam answer, and not leaving enough time to complete the remaining a
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