Why Is It So Hard To Find Feedback Control in Software Processes?
Meir M. Lehman
Department of Computing, Imperial College, London SW7 2BZ, UK.
Dewayne E. Perry
Software Production Research, AT&T Bell Laboratories, Murray Hill NJ 07974 USA.
Wladyslaw M. Turski
Institute of Informatics, Warsaw University, 02-097 Warsaw, Poland.
Initial investigations, using a basic model for feedback control, have exposed a variety of reasons why software processes are not amenable to classical feedback control: software processes are design, not production processes; control-directed process changes tend to be step functions, not regulatory ones, and are often as creative as the processes they control; and system development and evolution processes are still immature with little theory to guide the design and application of regulation control mechanisms. Despite these limitations, we have found promising examples of feedback control and, on the basis of more recent phenomenological evidence, believe this area of research to be critically important and vital to understanding and controlling the development and evolution of software systems and improvement of software processes.