Living with the Internet: Online shopping
Online shopping – think of it as a shopping centre in cyberspace, with online auctions as the car-boot sale in the car park. This unit will help you understand how to use online shopping sites, how to ensure that you are using the best sites and the best ways to protect your security. First publi
3.2 Combining data structures In Section 2, we introduced the notation SeqOfX for the set of all sequences whose members come from the set X. In Section 2, we looked only at sequences whose members were of one of the primitive forms of data (integers, characters or Booleans). We can have sequences whose members are themselves data with a more complicated form. For example, suppose that Jo is working at the till T1 and is replaced by Jessica. We might represent this handover by the 3-tuple (Jo, T1, Jes
3.7 How we work with numbers Most civilisations have had to face the problem of counting and recording numbers. Our own culture has adopted the so-called Arabic system of numbers. This system is now used more or less worldwide. In this section I will look very briefly at some of its key features. We have an infinity of numbers at our disposal. If we start counting from 1, we can in theory go on for ever. But although there is an infinity of numbers, we only have a very small, fixed number of digits to
9 Conclusion This unit started with the idea that computers have become an important part of everyday life, especially when all the ‘invisible’ computers that surround us are taken into account – those embedded in objects such as kitchen scales and digital cameras. Three fundamental ideas introduced in this unit are: computers comprise both hardware (the physical objects) and software (the programs); computers receive data from the ou
7.6 Arithmetic with binary fractions My final point in the preceding section brings home the fact that integer arithmetic is not really suitable when divisions are to be performed. It is also not suitable where some or all of the values involved in the arithmetic are not – or are not necessarily – integers, and this is often the case. In such cases, arithmetic has to be performed on non-integers. The most common representation for non-integers is the floating-point representation that I mentioned briefly in Box 3. You
4.5 Input and output considerations In this final portion of Section 4, I shall look in outline at how text, moving pictures and sound can be input into a PC and output from it. I'll leave aside the possibility that the data has been obtained by buying a disk or downloading via the Internet and assume that the user is creating it. I'll start by considering text, typed in at the keyboard. Pressing a key closes a contact and causes electrical current to flow. This enables the computer's keyboard input system to detect which
2.1 Introduction
Study note: You may like to click on the link below to the Numeracy Resource as you study Section 2. It offers additional explanations and extra practice on some of the topics, and you may find this useful. Click on the 'View document' link below to open the Numeracy Resource.
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):
2.2.1 Subsystems An important aspect of systems is that each component can be considered as a subsystem. In the health centre appointments system, the ‘computerised booking system’ may be a complex system in its own right involving a number of computers networked together. Figure 2 shows
4.8 Verification You will, perhaps, by now be getting a sense of the challenge of setting up an identification system on a national scale. However, for many routine purposes, establishing who a person is from an entire population of possibilities is not what is required. Instead what is required is confirmation that the person is who they claim to be. This is verification. An example of verification happens when you collect a parcel from a depot. You are sometimes asked to show your driving licence, pa
2.1 Modernising government Before we start to look at e-government itself, I would like you to read some quotations. During the 1980s and 1990s, the potential of ICT systems for government was discussed by many commentators, but in the UK the official argument for e-government was set out in 1999 in the document Modernising Government. This document, however, is not specifically about e-government. Rather, it is about the much broader issue of how government should be modernised. Here is an extract: 6.2.1 Threats, outcomes and impacts For the purposes of this unit, we define a threat to an information asset as a possible way in which the asset can have its security requirements breached, and we define the outcome of a threat as the way in which the asset's security requirements would be breached if the threatened action were to occur. Recall from Section 4 that the security requirements are confidentiality, integrity and availability. A complete picture of the relationship between an information asset, 4.1 Email attachments Following some simple rules should help you to minimise the risks from malware. The first rule is:
Never ‘double click’ to open a file attached to an email
Instead, what you should do is: Create a folder called ‘Attachments’ (or something similar) in an accessible location within your file structure. Mine is in ‘My Documents’ and is called ‘My Received Files’. 1 What this unit is about The recent huge increases in ownership of home computers and ever-widening access have been obvious boons to many peoples' lives but, as with many things that improve life, there is a downside. The downside with computers is that software crashes, hardware fails and some Internet users want to cause havoc or vandalise your computer. In this unit we will look at a few of the problems that other people may cause you. Normally when we talk about malicious software we are referring to virus 3.4 Databases An alternative to searching by simple text matching is to look inside a database specifically structured for genealogical searching. Probably the largest such database is freely available on the Internet. It has been constructed by the Church of Jesus Christ of Latter-day Saints (often abbreviated LDS and known as the Mormons) and is available through their FamilySearch website. Links from the home page of the FamilySearch website explain the purpose and background to the Church's interest in 7.6 Researching information about RFID tags What is the smallest RFID tag currently available? Use the Web to see what you can come up with but don't spend longer than 10 minutes on this activity. (Hint: using ‘smallest RFID tag’ as the search term w 5.4 Conclusion You have seen that although the three products you have looked at are very different types of computer, they all embody the same basic functionality and a version of Figure 3 can be drawn for each product to illustrate this. One feature of the PC is the range of forms of secondary memory it can use, and 5.2.2 Optical fibre In all developed countries, long-distance communication links (which used to be called ‘trunks’, by analogy to ‘trunk road’) nearly always use optical fibre. It is only where the terrain makes it difficult to lay a cable (such as in mountains or, sometimes, between islands) or when a new link is needed quickly and there isn't time to lay a cable that microwave links are used instead. An optical fibre is a strand of glass or plastic, not much thicker than a human hair, which guid 2.1 Introduction In this section you will be spending time exploring a number of resources on the Web. As someone who is interested in ICTs, it is important that you feel confident about keeping up to date with technological developments. The Web is one of your best sources of information and news in this subject area, but you will need to develop a critical eye in order to sift through and analyse the material that you find online. References
Activity 32: exploratory
