Chapter 1 - Introduction

Abstract

This introductory chapter discusses middleware as an infrastructure for distributed systems. An infrastructure is needed for distributed systems that suitably supports the development and the execution of distributed applications. A middleware platform presents such an infrastructure because it provides a buffer between the applications and the network. The network merely supplies a transport mechanism; access to it depends heavily on technological factors and differs among various physical platforms. Middleware homogenizes access to networks and offers generic services for applications. It also bridges technological domains and encapsulates the differences among different systems. Middleware can be described from two different perspectives: from the view of applications programmers and from the view of systems programmers. Applications programmers regard middleware as a tool that helps them in the development of distributed applications. These programmers are not normally interested in the implementation of middleware but only in its usage. Systems programmers take a complementary view. They regard the distribution platform as a white box and are interested primarily in its internal processes.