Consider a large university library. Tens of thousands of books,

periodicals, and other information resources are available for use. But

to access these resources, a categorization scheme must be developed. To

navigate this large volume of information, librarians have defined a

classification scheme that includes a library of congress classification

code, keywords, author names, and other index entries. All enable the

user to find the needed resource quickly and easily.            Now,

consider a large component repository. Tens of thousands of reusable

software components reside in it. But how does a software engineer find

the one she needs? To answer this question, another question arises: How

do we describe software components in unambiguous, classifiable terms?

These are difficult questions, and no definitive answer has yet been

developed.R. S. Pressman. Software Engineering - A Practitioner's Approach, 4 edn, th New York: The McGraw-Hill Companies Inc. 1997, p. 743 (with adaptations).From the text above, it can be concluded thatit was so difficult to access reusable software that only now has an answer been found to solve this problem.