Chapter 10. Testing and Logical Fault Tolerance for Parallel Programs
Those are places that can't be accessed from a Chaos Gate. If you try to enter, you show up, see a warning indicator, and then you're warped back to town.
|--Miu Kawasaki, .hack// Another Birth|
In Chapter 8, we introduced the Predicate Breakdown Structure (PBS) of an application and the Parallel Application Design Layers (PADL) analysis model. These are top-down approaches to producing declarative architectures for applications that have a concurrency or parallel programming requirements. One of the ultimate goals of PBS and PADL is to establish a chain of possession or audit trail for the application concurrency requirements that lead from the solution model to threads or processes at the operating system level. In this chapter, we connect the PBS and PADL analysis to application software testing and exception handling. The PBS and PADL tell you what you should be testing for and what constitutes an error or an exception. You can use exception handling to provide a kind of logical fault-tolerance for declarative architectures. That is, if your application for unknown and uncontrollable reasons violates statements, assertions, rules, predicates, or constraints from the PBS, you want to throw an exception and gracefully exit because once the predicates have been violated, then the correctness, reliability, and meaning of the application has been compromised.
In this chapter, we also introduce the various types of ...