Software reuse issues and perspectives

Software reuse could be implemented at several levels including the specification level, design level, program/subprogram library level, code level, and object-code level. However, reuse has a distinct definition for each of the above-mentioned levels. Moreover, the techniques applied to organize and manage reuse is different from one level to another. What's more, the complexity of the reuse methods and techniques increases as it moves from the specification level to the code and object-code levels. On the positive side, the time and space efficiency resulting from the application of reuse techniques improves in the same direction. Specification and design levels are at higher levels of abstraction than the other reuse levels, therefore their potential for accommodating reuse is greater and their adaptation to new applications can be simpler. However, the reuse process of the specification and design levels ultimately involves coding (be it system-generated or manual), testing, and debugging. On the other hand, reuse at code and object-code levels essentially eliminates coding and overall testing, hence it is more economical where a large collection of reusable software is organized in a software library