1.2 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.”
>>Difference between Software and Other Systems
Now lets talk something about how a software system is different from any other systems. For example, how software is different from a car, a TV or the similar systems or what is the difference between software engineering and other engineering like mechanical or electrical engineering. Lets look at some of the non-software systems like TV, Car or an Electric Bulb. The car may be malfunctioned due to some problem in engine while driving. Similarly an electric bulb may be fused while glowing and a TV could be dysfunctional while working.
So the major thing that distinguishes a software system from other systems is that;
“Software does not wear out!”
What does that mean?
As we have seen in above example that our non-software systems could be malfunctionedor crash while working. That mean they are affected by the phenomenon of wear and tear. They have a particular life and after that they could have some problem and may not behave and perform as expected. But this is not the case with software. Software systems does not affect by the phenomenon of wear and tear. If a software has any defect then that defect will be there from the very first day and that defect normally called bug. That
means if a software is not working then it should not work from the very first day. But this could not be the case that at a particular point in time a software is functioning well and after some time the same software is not performing the same task as required. So software does not have the element of wear and tear. Lets elaborate this point further. We have just talked about software defects which we call bugs. If a part of a car became wear out you just need to get a new one from market and replace the damages one with the new one. And the car will start working properly as it was working previously. Similarly if an electric bulb got fused then you just need to get a new one and put into the socket in place of the fused one and your room will again be illuminated. But the case of software is somewhat different. If a software has a bug then the same process of replacing faulty part with the new one may not work. You cannot remove the bug by just replacing the faulty part of software with the new one. Or it will not be as simple that, you go to the concerned company, get a new CD of that software and it will start working properly. If the software has a bug and that bug was present in the older CD then that will remain in the new one. This is a fundamental difference between software and other systems.
Source of Inherent Complexity of Software
Here the subject is again the same that how software systems are different from other systems. Have you ever noticed that how many different models of a car do a car manufacturing company release in a year? And how many major changes are made in new models and what is the frequency of these changes. If you think a little bit on it then you will realize that once the system is finalized then the changes in new models are of very minor nature. A drastic change is very unlikely in these kinds of systems. So the frequency of changes in these systems is very low and of minor nature. Like body shape could be changed a little, a new gadget could be added and the like but it is very unlikely that a fundamental change in engine is made. On the other hand if you observe the activities of a software manufacturing company, you will realize that these companies
make changes of fundamental nature in their software systems. They constantly change their systems whether in the form of enhancements, in the form of interface change or they are making a new system altogether. In other words they are making changes in their systems in many different dimensions. But in non-software systems these kind of changes are not that much frequent. One of the major reasons of increased bugs in software systems is this high frequency of change. You can well imagine that if a car manufacturing company manufacture cars in the similar way then how long these cars will remain useful, how much effort they have to put to design these cars, how much time they will require to mature the design, and how much time they would be needing to start production of such cars. If they try to cut-short that time, meaning that if they try to
release cars after every six-months or a year without proper testing and that release has a fundamental change then that kind of cars will also have lots of bugs and will not be road-worthy.
Therefore one of the major reasons of complexity in software is due to its basic nature that the software passes through a constant process of evolution. The name of the game is change and evolution all the times in all the dimensions. This change has the direct impact on software in the form of defects. Therefore software engineers also have to deals with the challenge of managing this process of change and evolution.
In the next post we will discuss Software Crisis.
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.”
>>Difference between Software and Other Systems
Now lets talk something about how a software system is different from any other systems. For example, how software is different from a car, a TV or the similar systems or what is the difference between software engineering and other engineering like mechanical or electrical engineering. Lets look at some of the non-software systems like TV, Car or an Electric Bulb. The car may be malfunctioned due to some problem in engine while driving. Similarly an electric bulb may be fused while glowing and a TV could be dysfunctional while working.
So the major thing that distinguishes a software system from other systems is that;
“Software does not wear out!”
What does that mean?
As we have seen in above example that our non-software systems could be malfunctionedor crash while working. That mean they are affected by the phenomenon of wear and tear. They have a particular life and after that they could have some problem and may not behave and perform as expected. But this is not the case with software. Software systems does not affect by the phenomenon of wear and tear. If a software has any defect then that defect will be there from the very first day and that defect normally called bug. That
means if a software is not working then it should not work from the very first day. But this could not be the case that at a particular point in time a software is functioning well and after some time the same software is not performing the same task as required. So software does not have the element of wear and tear. Lets elaborate this point further. We have just talked about software defects which we call bugs. If a part of a car became wear out you just need to get a new one from market and replace the damages one with the new one. And the car will start working properly as it was working previously. Similarly if an electric bulb got fused then you just need to get a new one and put into the socket in place of the fused one and your room will again be illuminated. But the case of software is somewhat different. If a software has a bug then the same process of replacing faulty part with the new one may not work. You cannot remove the bug by just replacing the faulty part of software with the new one. Or it will not be as simple that, you go to the concerned company, get a new CD of that software and it will start working properly. If the software has a bug and that bug was present in the older CD then that will remain in the new one. This is a fundamental difference between software and other systems.
Source of Inherent Complexity of Software
Here the subject is again the same that how software systems are different from other systems. Have you ever noticed that how many different models of a car do a car manufacturing company release in a year? And how many major changes are made in new models and what is the frequency of these changes. If you think a little bit on it then you will realize that once the system is finalized then the changes in new models are of very minor nature. A drastic change is very unlikely in these kinds of systems. So the frequency of changes in these systems is very low and of minor nature. Like body shape could be changed a little, a new gadget could be added and the like but it is very unlikely that a fundamental change in engine is made. On the other hand if you observe the activities of a software manufacturing company, you will realize that these companies
make changes of fundamental nature in their software systems. They constantly change their systems whether in the form of enhancements, in the form of interface change or they are making a new system altogether. In other words they are making changes in their systems in many different dimensions. But in non-software systems these kind of changes are not that much frequent. One of the major reasons of increased bugs in software systems is this high frequency of change. You can well imagine that if a car manufacturing company manufacture cars in the similar way then how long these cars will remain useful, how much effort they have to put to design these cars, how much time they will require to mature the design, and how much time they would be needing to start production of such cars. If they try to cut-short that time, meaning that if they try to
release cars after every six-months or a year without proper testing and that release has a fundamental change then that kind of cars will also have lots of bugs and will not be road-worthy.
Therefore one of the major reasons of complexity in software is due to its basic nature that the software passes through a constant process of evolution. The name of the game is change and evolution all the times in all the dimensions. This change has the direct impact on software in the form of defects. Therefore software engineers also have to deals with the challenge of managing this process of change and evolution.
In the next post we will discuss Software Crisis.
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