Software Fundamentals

1
Software Fundamentals

• Collected Papers by Parnas

2
On the Criteria to Be Used in Decomposing Systems
into Modules
December 1972

• Introduction by Weiss
• Idea module is a work assignment. Hides a design
  decision information hiding.
• Idea at run-time, one might not be able to
  distinguish what criteria were used to decompose
  the system into modules. A module may be a
  design-time entity or a load-time entity or an
  entity created at some other time.

3
Weiss

• AOP, a current vogue in programming technique,
  appears to be a rediscovery of the use of binding
  time in creating modular designs.
• Idea Every information hiding module should have
  an interface.
• Idea To evaluate a modular decomposition
  changes it accomodates.
• Compare business goals with easily accommodated
  changes startegic software engineering.

4
Weiss

• Idea Hierarchical structuring and modular
  decomposition are two different concepts. Modular
  decomposition leads to hierarchy but only one of
  many. Implicit is the idea of using different
  design structures to separate different concerns.