2.3 Models of an ICT system 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. Firstly, in the next few sections, we'll look at ICT systems where the primary function is to convey data. We can think of these systems as communication systems and I'll use a mobile phone system as an example. In sections 8–14, I'll focus on ICT systems wher
2.1 Introduction 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 electrical systems. 6 A look to the future So what will computers do for you next? Perhaps they will be the key to solving transport problems. Driverless cars, controlled by computers, are under development. If these ever come to fruition perhaps they could help to reduce the number of road traffic accidents by automatically reducing their speed when they come too close to another car. Or perhaps journeys could be made faster and less frustrating because cars will use communicating computers to analyse traffic density and move along t 5.2 Electronic kitchen scales A set of electronic kitchen scales is shown in Figure 7. Their basic operation is relatively simple. When they are switched on and, for example, a 500-gram object is placed in the scalepan, the display shows the digits 500 and the letter g. 2.4 Computer systems (contd) As I have already mentioned, the functional blocks shown in Figure 3 relate very closely to, even though they are not necessarily identical with, the computer's physical components. The computer's physical components are normally known collectively as the hardware. Software is a term often used to refer to a 2.1 Processors Figure 2 shows an advertisement for a laptop. The main features of the computer are listed in this advert. One item on the list is ‘Processor: AMD E450 1.65 GHz’. So this computer uses an AMD E450 processor, running at a speed of 1.65 GHz. A processor is an essential component of a computer; it carries out, or executes, the instructions that make up the computer program. PCs use one main processor and several other ‘supporting’ processors, and adverts for PCs often specify what main p Further reading References Keep on learning   There are more than 800 courses on OpenLearn for you to 5.1 Introduction The final approach to developing distributed systems is based on a radical view of such systems. The approach is based on work carried out by two American academics, Nicolas Carriero and David Gelerntner. These two academics developed a language known as Linda in the 1980s. The language, and its associated technology, has always been thought of highly by other academics within the distributed systems area, but has never taken off in terms of commercial use. However, in the late 1990s Sun deve 4.1 Introduction Many of you will already be familiar with event processing if you have developed visual interfaces with the later versions of Java. Developing such an interface consists of a number of steps: A visual object such as a button is placed in a container such as an applet or a 2.3 Synchronous and asynchronous message passing Synchronous message passing involves one entity (usually a client) in the message passing process sending a message and a second entity (usually a server) receiving it, carrying out some processing and then sending back some response which the first entity processes in some way. While the second entity is carrying out the processing the first entity pauses waiting for the response. In asynchronous message passing each entity in the process does not have to wait for the next part Learning outcomes After studying this course, you should be able to: describe some of the architectural and programming paradigms used in distributed system development describe message passing and the role of protocols within a message passing paradigm introduce the concept of a distributed object describe how event-based architectures are used within distributed system development introduce one implementation of an event-based architec Further reading References Conclusion This free course provided an introduction to studying Computing & 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. 6.2.15 Free products and services It might seem paradoxical to include sites which provide free products or services under the category of business models. Typical sites which come under this category include gaming sites where users can play computer games using their browser, sites which run free raffles and sites which offer free software. Such sites do not earn any revenues from the products or services they offer; revenue is earned indirectly, for example by means of banner adverts or by receiving revenue from site 6.2.7 Information brokerage Websites described by this business model offer access to information – usually business information. For example, a website which offers the results of surveys of customer satisfaction for a product such as a car would be used by car hire companies, auto companies and consumer organisations. Major providers in this area provide information derived from financial data such as company performance figures, pension fund performance figures and financial market trends such as the growth of diff 6.2.6 Third party marketplaces A third party marketplace is characterised by websites which offer access to a number of related companies, for example companies that are wholesalers of office stationery. A distinguishing feature of this model is that the companies delegate the marketing and sales of their products to the company that administers the marketplace. Typically a website which operates as a third party marketplace would provide a common interface to the products or services which are being sold, together with fa 6.2.5 Virtual communities A virtual community is a website which sells some product or service. In this respect there is no difference from an e-shop. The feature which distinguishes a virtual community is that the operator of the website provides facilities whereby the customers for a product or a service interact with each other, for example by pointing out ways a product can be improved. Technologies used for this interaction include mailing lists, bulletin boards and FAQ lists. The theory behind virtual communitie
Activity 1 (exploratory)
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