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So, let's see how this affects the concept of software
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quality. Another way to express what we just said is
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to say that the software runs on some hardware and
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is developed for a purpose that is related to human
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activities. And given this perspective, we can define what we
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mean by software quality in this light. Software quality is
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not just a function of the software. So, the software
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itself does not define the quality of the overall system.
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Rather, software quality is a function of both the
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software and its purpose. Where purpose has to do with
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the way in which the software will be used. So
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a software system can be of low quality not only
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because it does not work well. So, for example, not
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only because it crashes. Of course, that's an issue. But
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just as importantly, a software can also be of low
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quality because it does not fulfill its purpose, and this
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happens quite often. It is unfortunately not rare for
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the software producers to have an inadequate understanding, or even
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a complete misunderstanding of the purpose of the software,
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of what the users want to do and will do
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with it. Turning these around, we can therefore define
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the quality of software in terms of fitness for purpose.
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The more the software fulfills its purpose, the more
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the software is on target, the higher is its quality.
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And identifying the purpose of the software, so hitting
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this target, is exactly the goal of requirements engineering.
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And it is the reason why requirements engineering is
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such a fundamental activity in the context of software engineering.
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