Building Software Using the Sequential File Model

Conventional software tools have been based on the sequential file processing model. Sequential file processing is implicit in the concept of a "compiler." The figure shows the standard process for building an executable program from one or more source files.

The sequential file processing model has infiltrated all software application design. Those of you who know UNIX understand that its shell languages are based on the convention that every UNIX application is a file-in/file-out process.

As applications became more interactive (the technical term is "event-driven") using windows and mice, we bent the software construction model we understood, namely the file processing model, so that programs would behave correctly. The consequence of this stereotypical approach to building the new applications is that the internal structures of interactive applications are now so obscure that it’s impossible to explain to someone who is not an experienced object-oriented programmer how a typical Macintosh or Windows application actually works.