1 Representing data in computers: introduction A computer is designed to do the following things:
receive data from the outside world;
store that data;
manipulate that data, probably creating and storing more data while doing so;
present data back to the outside world. In the next few sections I am going to examine in more detail the data that a computer receives, stores, manipulates and presents. I
14.3 Personal Digital Assistants
Personal Digital Assistants (PDAs) or handheld computers are small, portable computers. They each contain a small processor and have specially written operating systems. Two popular types of PDA at the time of writing (early 2005) are those running the Palm OS operating system and those using the Windows Mobile operating system, (also called Pocket PC). There is a range of applications purposely written for PDAs, but many also use special versions of popular applications like Microsof
4.2.1 First computer (your computer) In the block diagram, the computer receives data from the user and sends it into the network. It will manipulate and also store and retrieve data. If you send a message to a FirstClass conference, your computer receives the message from you as data via the keyboard. The computer manipulates the data into a form that can be sent into the network, in this case the internet via your internet service provider (ISP). Your computer will also store or retrieve relevant data, such as details of
14.1 Introduction Now that I have introduced you to the processes carried out by a stand-alone computer, I will move on to discuss what happens when computers are linked.
6.1 Networks Next I'll be looking more closely at the ‘network’ block in Figure 8, and in particular at the links that must be present before communication can take place. I'll introduce you to just a few of the forms that these links can take; links may be physical ones, such as cables, or they
5 The processes My description of the three subsystems of ‘means of conveying a message’ has indicated some important processes that each carries out. These are shown in Figure 8. The key processes are those that will always be carried out and they are shown in bold; the other processes may or may
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
1.6.6 Problems with the use of sound Pre-recorded digitised speech can be included in a UI relatively easily, but generating speech is harder. One of the methods for synthesising speech is called concatenation. The idea behind concatenation is that the computer stores sentences, phrases or word segments of real human speech. New sentences are constructed by arranging words in the right order. For example, with current telephone directory enquiry systems in many countries, after having made an enquiry of a human operator,
3.3 Incentives Reread the short section entitled ‘Benefits of an information security management system’ at the end of Chapter 1 of IT Governance: A Manager's Guide to Data Security & BS 7799/ISO 177799 (the Set Book). In light 3.2.3. Regulation and codes of conduct Chapter 1 of the Set Book presents a case for effective information security based largely upon perceived threats and legal obligations. Chapter 2 introduces further imperatives, which govern specific types of organisation in the UK. 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’. 2.2 Browsing for information on the Web One way to find what you are looking for on the Web is to start from sites that you know are likely to have useful ‘links’ on them, like the main Open University pages or the Open University Library pages. These opening pages are known as home pages and are a bit like the contents page of a book. The home page usually gives you some information about the content of the website, often with links to other pages of information held on that site and on sites elsewhere. By clicking on a link â 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 7.5 Active and passive tags Read the extracts below. Using the information they contain, make notes about the main differences between active and passive RFID tags. You will get more out of this exercise if you make a serious attempt to d 4.7 WiFi data rates and operating range Just as for Ethernet, developments in technology have increased the achievable data rates since the first WiFi standard was developed in 1997. At the time of writing, the latest WiFi standard to be published – IEEE 802.11g – defines a data rate of 54 Mbps. 5.1 The personal computer Over the following screens you will look at three different examples of computers: a PC, which is obviously a computer, and a set of electronic kitchen scales and a digital camera, which are not so obviously computers. You will find that all three of these examples match with the functional block diagram of a computer given in Author(s): 7.2 Difficulties in navigating e-commerce sites People who are new to computing sometimes find the process of online ordering baffling and frustrating. They get ‘lost’ in the process – for example, by putting something into a virtual shopping cart and then remembering that there's something else they need to look for. So they return to the search engine or the catalogue and then can't find the cart. These kinds of commonly experienced difficulties can be addressed by good and adaptive site design, but still a disturbing proportion of 2.1.1 What's ‘Buy It Now’? 2.4 Comparing early sources of news
Taylor compares the merits of radio and newsreels, as sources of news, with those of newspapers. 4.3.2 Plagiarism
Attempting to pass off someone else's work as your own is plagiarism.
You may be encouraged to use the Web as a resource for writing assignments. This does not mean you should copy chunks of text from other websites however. You can quote from other sites, but such quotes should always be acknowledged. You should write material in your own words, to demonstrate that you have understood it, rather than simply copying it. Using search engines it is relatively easy for markers to
Activity 8
Activity 6
Activity 32: exploratory
Activity 30: exploratory
Activity 17: exploratory
Radio and newsreels
