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8.4 The OR operation The OR operation (occasionally called the inclusive-OR operation to distinguish it more clearly from the exclusive-OR operation which I shall be introducing shortly) combines binary words bit by bit according to the rules: 0 OR 0 = 0 0 OR 1 = 1 1 OR 0 = 1 1 OR 1 = 1 In other words, the result is 1 when either bit is 1 or when both bits are 1; alternativel
16.2.1 Receiving data In a supermarket ICT system, there needs to be some way for the computer to receive information about the items a customer is buying. Think back to a recent visit to your local supermark 12.1 Introduction 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 quickly. Data may be stored on the stand-alone computer's hard disk in the form of files. You may want to move files from one stand-alone computer to another. In addition, you may want to move files from a device, such as a digital camera, to a computer. These activities require some fo 10.1 Introduction 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. Data may be output via devices such as a screen or a printer. There are many different ways of getting data into a computer. For example, a scanner converts images and texts into a format that can be processed by the computer and displayed on screen. Devices such as t 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 may be wireless, such as radio links. I'll also d 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. Further reading 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 Further reading 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 6.2.4 E-mall An electronic mall or e-mall is a collection of e-shops which are often devoted to a specific service or product, for example an e-mall might be devoted to selling goods associated with a leisure activity such as fishing. Usually e-malls are organised by a company which charges the e-shops for administering their presence: maintaining the website, hosting the e-mall, and providing payment and transaction facilities and marketing. The e-mall operator gains revenue for charging the e-shop 2.5 Other commercial websites So far I have detailed e-commerce applications which are connected with very large organisations; to conclude this section it is worth looking at a number of smaller applications, many of which are distinguished by the fact that they are novel. They are in contrast to the applications discussed in previous subsections which mainly consist of standard functions such as order processing. 2.4 Auction sites These are sites on the web which run conventional auctions. There are two types of auction: those that are carried out in real time, where participants log in to an auction site using a browser at a specified time and bid for an article until the highest price is reached and no other bids are forthcoming. The other type of site – and the most common – is where an item is offered for sale and a date advertised after which no more bids are accepted. Such sites make a profit from two sources 2.1 An example – supply chain management Before looking at the wide variety of e-commerce application areas that have flourished over the last decade in more detail, it is worth looking at one which may not be familiar to a reader, but which saves companies huge amounts of resources. The application involves a supply chain. A supply chain is a set of relationships between a number of companies who have a symbiotic relationship with each other in that one company supplies commodities or services to other companies which, in tu
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