CMU CS 15-675 Architectures for Software Systems Spring 1998
Case Studies in Patterns
with answers
Garlan & Kazman Questions on Readings for Lecture 24 Due: Mon April 13, 1998
The papers:
[Abo93]: Structural Modelling.
[BC91]: Bass, Coutaz, pp. 170-184.
Hints:
The Abowd et al report provides an introduction to the history, requirements, and software problems facing flight simulators. It discusses a new pattern-based domain-specific software architecture, called a Structural Model, for flight simulation. Think about the base types of the structural model and how these provide a vocabulary of patterns for building a complex software architecture.
Bass and Coutaz describe an architectural style, called PAC (Presentation - Abstraction - Control), for building the user interface portion of interactive systems. When reading this section, think about the advantages of building a system from such a restricted set of primitives as those presented in the PAC architecture. What are the disadvantages?
Questions:
1) Describe the function of each of the parts of a PAC agent.
Presentation: the perceivable behaviors, input and output
Abstraction: the functional core of the application
Control: links the abstraction and presentation and maintains relationships with other agents
2) What is the function of export areas in the structural model?
To decouple producers and consumers of information. In particular, to decouple subsystems from explicit knowledge of each other.
Modified: 5/21/98