TRANSCRIPTS
On the operations side of things, ICT is used in stock control, recording stock coming into the company and tracking that stock through the production process until the finished product is sent to the customer. It can also be used to reorder stock. Computer-assisted manufacturing – CAM – is a feature of many of today’s car manufacturing companies, where some or all of the machines used in the production line are computerized. In some cases, a computer system will also control the production environment, for example where a product needs to be kept at a certain temperature.
Unit 1, Lesson 4, Exercise D Lecture 2
≤1.7
So what are the causes of computer bugs? Well, bugs can occur in either a software program’s source code or in its design, and they are usually a result of errors made by developers. For example, a programmer may have made a mistake when writing the source code, or the different parts of a program may interact in a way that wasn’t predicted at the design stage.
The effects of a computer bug can be mildly inconvenient or they can be catastrophic. In some cases, you might not even realize a software program has a bug – this is because the bug has no effect, or a very minimal effect, on the program’s functionality. In other cases, a bug may cause programs to crash – that is, stop working altogether. In such cases, the bug will result in considerable inconvenience to the user. Even more serious than this is the fact that bugs can cause security problems, laying a system open to viruses.
There have been a number of cases where computer bugs have had extremely serious consequences. In some cases, these have been financial. For example, a computer bug resulted in the loss of the billion-dollar Ariane 5 rocket in 1996. Fortunately, this didn’t result in the loss of life. However, a software bug in the Therac-25, a radiation therapy machine, is thought to have led to a number of cancer patients being given overdoses of radiation between 1985 and 1987.
Unit 1, Lesson 4, Exercise D Lecture 3
≤1.8
The term ‘waterfall model’ was coined by Winston Royce, a software engineering researcher, in 1970.
The waterfall model can be broken down into five basic units. The first stage is requirements
specification. This is the stage when a systems analyst looks at an existing system, either manual or computerized, to see how things can be improved. At this point, the systems analyst will watch people using the system, collect information from users, and look at documentation. This will help him or her to identify the shortcomings of an existing system and produce a description of what the new system should do. The second stage is systems and software design. It is the responsibility of a software designer, or architect, to study the systems specifications and turn these into design documents for programmers to work from.
In the third stage, the development stage, a team
of programmers creates the new software. Each programmer is allocated a part of the software to produce, so, although they are a team, they will be doing different things and progressing at different rates. For this reason, it isn’t possible to test the system as a whole, so developers will test their own work as stand-alone units.
The fourth stage is integration and systems testing. When all of the separate parts of the system have been finished, it should be possible to integrate them – that means, fit them together, and test the system to see if everything works.
The final stage of the waterfall model is installation, operation and maintenance. At this point, the new system is installed and staff are trained to use it. From then on, the day-to-day running of the new system is the responsibility of the systems administrator.
Unit 1, Lesson 4, Exercise D Lecture 4
≤1.9
Sputnik 1, the world’s first artificial satellite, was launched by the Soviet Union in 1957 and marked the beginning of the ‘Space Race’ between the United States and the Soviet Union. Faced with losing the lead in military science and technology, the US government set up the Advanced Research Projects Agency, ARPA, in 1957. By 1969, ARPA had created ARPANET, a small network of computers in different cities which could communicate with each other. The technology behind ARPANET gave the US Department of Defense a method of communicating in the event of a nuclear attack, when normal methods of communication might not be feasible.
It rapidly became apparent that ARPANET could have other peace-time uses, and by 1972, scientists and academics around the US were using the system to exchange ideas and information. In
115
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40 |
Page 41 |
Page 42 |
Page 43 |
Page 44 |
Page 45 |
Page 46 |
Page 47 |
Page 48 |
Page 49 |
Page 50 |
Page 51 |
Page 52 |
Page 53 |
Page 54 |
Page 55 |
Page 56 |
Page 57 |
Page 58 |
Page 59 |
Page 60 |
Page 61 |
Page 62 |
Page 63 |
Page 64 |
Page 65 |
Page 66 |
Page 67 |
Page 68 |
Page 69 |
Page 70 |
Page 71 |
Page 72 |
Page 73 |
Page 74 |
Page 75 |
Page 76 |
Page 77 |
Page 78 |
Page 79 |
Page 80 |
Page 81 |
Page 82 |
Page 83 |
Page 84 |
Page 85 |
Page 86 |
Page 87 |
Page 88 |
Page 89 |
Page 90 |
Page 91 |
Page 92 |
Page 93 |
Page 94 |
Page 95 |
Page 96 |
Page 97 |
Page 98 |
Page 99 |
Page 100 |
Page 101 |
Page 102 |
Page 103 |
Page 104 |
Page 105 |
Page 106 |
Page 107 |
Page 108 |
Page 109 |
Page 110 |
Page 111 |
Page 112 |
Page 113 |
Page 114 |
Page 115 |
Page 116 |
Page 117 |
Page 118 |
Page 119 |
Page 120 |
Page 121 |
Page 122 |
Page 123 |
Page 124 |
Page 125 |
Page 126 |
Page 127 |
Page 128 |
Page 129 |
Page 130 |
Page 131 |
Page 132 |
Page 133 |
Page 134 |
Page 135 |
Page 136 |
Page 137 |
Page 138 |
Page 139 |
Page 140
