Software Evolution:

Software Evolution

Earnest Tellow, a well known in the field of intelligence, compared the evolution of software technology to the growth of tree. Like a tree, the software evolution has had distinct phases or layer of growth.Thes layers were built up one by one over the last five decades as shown in fig.

1.3, with each layer representing an improvement over the previous one. However, the analogy fails if we consider the life of these layers. In software system, each of the layers continues to be functional.

Alan Kay, one of the promoters of the object-oriented paradigm and the principal designer of Smalltalk, has said, as complexity increases, architecture dominates the basic material. To build today’s complex software it is just not enough to put together a sequence of programming statements and sets of procedures and modules, we need to incorporate sound construction techniques and program structures that are easy to comprehend ,implement and modify. Science the invention of the computer, many programming approaches has been tried. These include techniques such as modular programming, top-down programming, and bottom-up  programming and strutted programming .The primary motivation in each has been the concern to handle the increasing complexity of programs that are reliable and maintainable. These techniques have become popular among programmers two decades.