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Time: 9 hours
Level: Introductory
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 Introduction Resource- This unit will introduce you to some ideas about how information and communiction technologies (ICTs) systems work. We will look at how ICT systems convey, store and manipulate data, and how they process...
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| | 1 Describing an ICT system
- 1 Describing an ICT system Resource
- In this unit I shall be introducing you to some ideas about how ICT systems work. Because this unit is about ICT systems, I'll be starting with a discussion about what constitutes a system. I'll go on...
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- 2.1 Introduction Resource
- There are many types of system – not just ICT systems. For example, we all have a nervous system and, as you are studying T175, you are in a higher education system. Our homes have plumbing systems and...
- 2.2 A system map Resource
- One way of explaining and analysing a system is to represent it in a graphical form, known as a system map. I'll use the example of a system for making an appointment with a doctor in a health centre to...
- 2.3 Models of an ICT system Resource
- To help me to introduce you to important ideas about ICT systems, I'm going to take a three-stage approach. ICTs involve conveying, manipulating and storing data. This is going to be the basis of my approach....
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- 3.1 Introduction Resource
- Generally, when we talk about communication between humans, we mean one person conveying information to another person. Figure 6 shows a basic model, or representation, of a communication system for getting...
- 3.2 Looking into the 'means of conveying a message' Resource
- 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...
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- 4.1 Introduction Resource
- I'll now look at what these components do in the communication system, using the mobile phone system as an example.
- 4.2 The transmitter Resource
- The transmitter receives a message from User 1 and manipulates it into data which can be sent into the network. The transmitter may also store or retrieve data relating to the message.
- 4.3 The network Resource
- The network is a communication channel in that it conveys data from the transmitter to the receiver. The network may also manipulate data in some way, and it may also store or retrieve data.
- 4.4 The receiver Resource
- The receiver receives data from the network and manipulates it into a message to send to User 2. Sometimes the receiver may also store or retrieve data.
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- 5 The processes Resource
- 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...
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- 6.1 Networks Resource
- 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...
- 6.2 Working with bits Resource
- You may have met the term bit, perhaps in connection with computers. The term ‘bit’ is also important in communication systems. It is an abbreviation for ‘binary digit’. A binary digit can have just one...
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| | 7 Describing an ICT system: conclusion
- 7 Describing an ICT system: conclusion Resource
- We have arrived at a model of a communication system that illustrates the processes needed for communication. We have also looked at the different kinds of communication link that can be used to convey...
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- 8 Computers Resource
- In sections 8–14, I am going to start by considering a stand-alone computer, which is a computer that is not connected to a network. In this type of ICT system, the key processes are the manipulation and...
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- 9 A stand-alone computer Resource
- The computer you are using for your studies is called a personal computer or PC. Although you have an internet connection for use in this course, your computer can probably also be used as a stand-alone...
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| | 10 Sending and receiving data
- 10.1 Introduction Resource
- A stand-alone computer receives data from a user by means of input devices. The two most commonly used input devices are the keyboard and the mouse. A computer sends data to a user by means of output devices....
- 10.2 Ports Resource
- On the outside of a computer you will see a number of connection points that look like sockets. These sockets are known as ports and they provide connections between the computer and external devices such...
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- 11.1 Introduction Resource
- A stand-alone computer needs two main components to manipulate data: a processor and a working memory.
- 11.2 The processor Resource
- The processor can be thought of as the ‘brain’ of the computer in that it manages everything the computer does. A processor is contained on a single microchip or ‘chip’. A chip is a small, thin slice of...
- 11.3 Memory Resource
- An essential component of a computer is the memory which it uses to hold data currently being used by the processor. This is the random access memory (RAM), the computer's working memory in which programs...
- 11.4 Computer software Resource
- 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...
- 11.5 Programming languages Resource
- 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...
- 11.6 Operating systems Resource
- 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...
- 11.7 Applications Resource
- 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...
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- 12.1 Introduction Resource
- Data must be stored somewhere when it is not being manipulated. Modern ICT systems require increasingly large amounts of data to be stored for later use, and it is important that the data can be accessed...
- 12.2 Bytes of data Resource
- You will recall from Section 6.2 that a binary digit, or bit, can have one of two values: either a 0 or a 1. In a computer, bits are assembled into groups of eight, and a group of eight bits is known as...
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| | 13 Different types of storage
- 13.1 Introduction Resource
- 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...
- 13.2 Magnetic storage Resource
- As I mentioned earlier, your computer has a hard disk which provides a permanent storage area for your computer's programs and the files you create. When you save files to your computer's hard disk, you...
- 13.3 Optical storage Resource
- 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...
- 13.4 Flash memory Resource
- Flash memory is an electronic form of memory which can be used, erased and reused. A flash memory card is a small storage device used to store data such as text, pictures, sound and video. These...
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- 14.1 Introduction Resource
- 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.
- 14.2 Modelling networked computers Resource
- You met a block diagram showing a model of a communication system in Figure 8. In this model, a transmitter sends data into a network which conveys it to a receiver; but how does this model work when the...
- 14.3 Personal Digital Assistants Resource
- 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...
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| | 15 Computers and communication systems working together
- 15 Computers and communication systems working together Resource
- The combination of communication systems and computers has produced powerful new systems not possible when these technologies are used separately. In section 15–19, I'll be using an ICT system in a supermarket...
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| | 16 ICT systems in a supermarket
- 16.1 Introduction Resource
- Supermarkets make use of ICT systems for a range of purposes. In the following sections, we'll look at the processes of receiving, storing, retrieving, manipulating and sending data at the checkout, and...
- 16.2 Processes at the checkout Resource
- 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 Figure 12 represents this...
- 16.3 Networked computers in the supermarket checkout system Resource
- All these processes are very helpful for the purposes of dealing with an individual customer's purchases. However, when computers are linked in a network, many new uses are possible.
- 16.4 The network Resource
- The term ‘network’ is used to describe some very different interconnected systems. In a home setting, you might have just two computers linked together to share documents and devices (such as a printer...
- 16.5 The database server Resource
- A database is used to store data in a form that can be organised and searched. A supermarket may use a number of different databases in order to carry out its activities. I'll now discuss two examples...
- 16.6 Pricing and stock control Resource
- A supermarket has a large database of information about its goods, such as the name, price, size and quantity held in stock.
- 16.7 A loyalty card scheme Resource
- Supermarkets, and other types of retailer, use loyalty cards to encourage customers to use their particular shops. Points are awarded when a customer spends money in the shop. Supermarkets ‘reward’ their...
- 16.8 Linking data Resource
- We now have two sets of data held by the supermarket: the data about its own products and the personal data about customers. Individually, each of these two sets of information has important uses. However,...
- 16.9 Identity in an ICT system Resource
- In a supermarket we might see the following data on an item: 5018190009067. On their own, the digits do not mean very much, but these numbers are typical of the type of data input to a computer system....
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| | 17 Taking an overview of ICT systems
- 17.1 Introduction Resource
- I'm going to pause here to try to put together some of the ideas we have encountered so far. I deliberately chose the example of a supermarket to illustrate some of the key processes involved in an ICT...
- 17.2 The checkout terminal Resource
- The first computer block represents the checkout terminal. The processes at the checkout (receiving, storing, retrieving, manipulating and sending data to the user), are the same as I described earlier....
- 17.3 The network Resource
- The network conveys the data on items purchased through to the database server. It also conveys data such as revised prices and special offers from the database server back to the checkout terminal. In...
- 17.4 The database server Resource
- The computer block on the right represents the database server, which is dedicated to managing a database and making the data available to other computers in the network. The database server receives data...
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- 18.1 Introduction Resource
- Most supermarkets now have an online ICT system which allows customers to select and purchase goods from the supermarket's website. Goods are then delivered to the customer's home. Buying and selling things...
- 18.2 Using e-commerce Resource
- Many people now have internet connections and this offers many benefits to both businesses and their customers.
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- 19 Conclusion Resource
- In sections 15–18, we examined the components and processes of an ICT system that is used for an everyday activity: shopping. We started by looking at a system map of the ‘checkout system’ before exploring...
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| | References and Acknowledgements | |
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