Chapter 1 Flashcards

Question

What are some differences between software engineering and other forms of engineering?

Answer 1

1. Age 2. Cost 3. Flexibility 4. Innovation 5. Complexity 6. Reliability

Answer 2

Software engineering is an immature discipline, spanning roughly the last 50 years. Civil engineering, on the other hand, is thousands of years old. Software engineers have taken advantage of the wisdom and experience gained in other engineering disciplines to apply them to the software.

Answer 3

The cost of construction materials and labour (other than engineering labour) is significantly higher in other engineering disciplines, relative to the costs of a a compiler and a PC. As such, the percentage of engineering in a software system is notably higher than in other engineering disciplines, so delays and mistakes have a larger impact.

Answer 4

Software is generally quite flexible. This is related to the previous point on cost. It is more straightfor- ward to change something about a software system after it is built than for many other types of engineered products. For example, you would never ask a civil engineer to move a bridge 50 metres downstream one month before opening. However, software engineers are routinely asked to change major parts of a project just prior to release. Only with proper control can this be achieved.

Answer 5

Typically, software is more innovative than other engineered products. Due to the relative ease and low cost of replicating a piece of software, software engineers are often solving a problem that has never been solved before. As a result, software engineers often have to use more innovative solutions. Domain specificity: While all engineering projects have constraints on the product, such as their environment, software engineering projects are almost always domain specific, and often this requires the software engineers to understand to most important parts of the domain. For example, when constructing an office building, it is often largely irrelevant what the business of occupants of the building will be. However, for software, the domain of application is highly relevan

Answer 6

The level of complexity of a software application is generally much higher than in other forms of engineering. Large software systems contain a number of variables with many interactions between them that are difficult to understand.

Answer 7

Software systems are typically more unreliable than other engineered products. This is largely due to the factors already discussed: products are more complex; the field is less mature, so the tools and techniques cannot cope with this complexity; more innovative solutions are required, so there is less scope to use tried and tested techniques; software engineers cannot often obtain a good enough understand of the domain of the software; and the cost of replicating and re-deploying software is low enough that unreliable systems can be replaced more easily. Furthermore, people tolerate unreliable software systems more than other engineered products. An unreliable bridge, electrical product, chemical, etc., are likely to cause harm, whereas the average desktop application will not. We do find, however, that safety-critical software systems are engineered more carefully and rigorously than standard desktop application for this very reason, and are more reliable.

Answer 8

It is certainly possible for a group of genius programmers to get together and hack out a quality product, but this would be largely due to luck and individual brilliance. Unfortunately, there are not enough charmed geniuses in the world to support even a fraction of the requests of those wanting quality software, so we use software engineering to provide systematically and repeatedly build quality software.

Answer 9

The development of software engineering as a field came about from necessity. People building software found that they encountered many problems during construction, and so produced techniques to mitigate these. They found that applying many of these systematically results in repeatedly being able to build quality software, so they share these with the rest of the community. There are many different tools and techniques for many different types of systems, but software engineers will only create and adopt these tools and techniques if they believe that they help to solve some problem.

Answer 10

The reason the discipline of software engineering is becoming more important is because software is become more and more complex. As the power of computing increases, and the size of problems that can be solved in a reasonable time becomes larger, the ability to conceive and develop these solutions becomes more difficult.

Answer 11

Software engineering helps to manage this complexity using four broad disciplines: monitoring, controlling, analysis, and synthesis.

Answer 12

1. Misunderstanding of requirements 2. Design failures 3. Project management failures 4. Other he “other” entry here includes failure in team work, incorrect choices of technology, insufficient testing, insufficient configuration management. Therefore, what many people may consider as the typical software “bug” account for a small amount of software failures of released systems. Despite much of the careful planning and hard work that goes into many requirements documents, requirements account for more than half of all failures.

Answer 13

a programmer writing code that behaves differently to what they intended

Chapter 1 Flashcards

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