In many software projects only the first two levels of the developer-oriented information are taken into account. We'll briefly consider some others and describe their importance for a developer.
The next is the level of requirements. An user needs to know for which purposes he can apply a software component. The developer needs to know for which use he must make a software component. These are two views on the same information, two quite different views.
Let's say the coding of a component is the implementation of a tactical plan. The design is the preparation of this plan. The requirements are the goals of this plan. The design and coding are the answers on the question how. The requirements describe what. Abowe requirements is the level of strategy. It gives the answer on the question why.
By designing, creating or changing of a component the developer must decisions about requirements. This decisions determine the user-oriented, the computer-oriented and two lower levels of developer-oriented information. In many cases the requirements for a component are documented, but origins of them aren't. Consequently the more expensive strategical errors are much more complex to find.
For instance one developer was being written a class, that should hold a number of certain objects. He had decided to implement a double linked list. To optimise the speed of search he had applyed a complex algorithm. He had spent a lot of time for coding and testing. He had wrote good comments and explained the tricks he had used.
After some time the users of the class had found aa numbeffr of faults. To this moment the developer was left the project. One other developer had wasted a lot of time to understand and to correct the source code.
Accidentaly one team member asked him to simplify the interface of this class. This forced the developer to check how the class was used. He found only two cases of use and the maximal possible number of objects in the list was four. He had rewrote the class in a simple manner. The result was more comfortable and more reliable.