Unix as an Extensible System
“Complex software systems should be built incrementally from components.”
- independently developed
- replaceable, interchangeable, adaptable
The power of fork/exec/exit/wait makes Unix highly flexible/extensible...at the application level.
- write small, general programs and string them together
general stream model of communication
- this is one reason Unix has survived
These system calls are also powerful enough to implement powerful command interpreters (shell).