CS - 504 || Double Quiz of CS - 504 Quiz # 2 Solved By || Software Engineering || Vicky Lab

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Difference between Computer Science and Software Engineering

The science concerned with putting scientific knowledge to practical use. Webster’s Dictionary

There are many engineering fields like electrical, mechanical and civil engineering. All these branches of engineering are based on physics. Physics itself is not engineering but the use of physics in making buildings, electronic devices and machines is engineering. When we use physics in constructing buildings then it is called civil engineering. When we use physics in making machines like engines or cars then it is called mechanical engineering. And when we apply the knowledge of physics in developing electronic devices then the process is called electrical engineering. The relation of computer science with software engineering is similar as the relation of physics with the electrical, mechanical or civil engineering or for that matter the relation of any basic science with any engineering field. So in this context we can define software engineering as: ”This is the process of utilizing our knowledge of computer science in effective production of software systems.”

Software Crisis

What is Software Crisis?

Computer systems were very new and primitive in early fifties and the use of software was also very limited at that time. It was limited to some scientific applications or used to process the data of census. In 1960s a great amount of rapid improvement was made in hardware. New hardware and new computer systems were made available. These computer systems were far more powerful than the computers of early fifties. It is all relative, the computers of 1960s are primitive as compare to the computers we have these days but were far more powerful than the computers of early fifties. More powerful hardware resulted into the development of more powerful and complex software. Those very complex software was very difficult to write. So the tools and techniques that were used for less complex software became inapplicable for the more complex software. Lets try to understand this with the help of an example.

Let’s imagine a person who use to live in a village and who have constructed a hut for him to live. Definitely he should have face some problems in the beginning but was managed to build a hurt for him. Now if you ask him to construct another hut, he may be able to construct one more easily and in a better way. This new hut may be better than the first one and he may construct it in a relatively less time. But if you ask him to construct concrete and iron houses then he may not be able to handle it. Since he made a hut and he know how to make a place to live so you may expect from him to build concrete and iron buildings. If this is the case then you should all agree that the building constructed by that person will not have a stable structure or he may not even be able to build one.

In early 60s software had suffered from the similar kind of problem to which we call Software Crisis. Techniques that were used to develop small software were not applicable for large software systems.

Evaluating the Quality of an Object-Oriented Design

Judging the quality of a design is difficult. We can however look at certain objectoriented design attributes to estimate its quality. The idea is to analyze the basic principle of encapsulation and delegation to judge whether the control is centralized or distributed, hence judging the coupling and cohesion in a design. This will tell us how maintainable a design is.

You may also recall our earlier discussion of coupling and cohesion. It can be easy to see that OO design yield more cohesive and loosely coupled systems.