Explain why a software system that used in a real-world environment must change or become progressively less useful?

A system that is used in a real-world environment necessarily must change or become progressively less useful in that environment. And remember that software can’t be developed completely, as the requirement changes software becomes useless or worth so that there is need to update our system as per our requirements. As the system’s environment changes, new requirements emerge and the system must be modified. When the modified system is re-introduced into the environment, this promotes more environmental changes so the evolution process recycles.

There are certain reasons that makes software system which is used in real-world environment must change become progressively less useful as:

1. Number of users may increases, and then the burden of the system requiring is expanding to its hardware capability for handle several connections.

2. The business model of the company may change so the system become obsolete and need for a change to cope its requirements.

3. The law in the particular country may impose a particular standard which also effect to software systems.

Following figure shows Software reliability curve which means software doesn’t ware-out but it becomes progressively less useful due to some real-world environmental changes.