The JR Concurrent Programming Language

Errata for the JR Book

2004-08-05. p104, Exercise 8.5. Clarification: Give the exact translation to send/receive pairs of the invocation of p and the reply statement.

2005-07-20. p135, Exercise 9.32, 2nd sentence should be:
Process B has a set of integers, T.

2005-07-24. p332, rules for inni and view statements need a [] before the else; also, the first form of inni now allows an elseafter for timeout, so these three rules should now be:
      inni InniArm { [] InniArm} [ [] (else Statement)|(elseafter Expression Statement)]
      inni with Expression over InniSelectArm {[] InniSelectArm} [ [] else Statement]
      view Expression ViewArm {ViewArm} [ [] else Statement]

2005-07-25. We've changed the syntax (effective in JR versions after 1.00061) so that process quantifiers cannot be empty. So, simple changes to code:
p117, eliminate () after RWAllocator.
p125, eliminate () after FairRWAllocator.

2009-08-19. We've updated the sample code from Chapter 5 (Synchronization Using Shared Variables) to more accurately reflect Java's Memory Model. Specifically, we added the keyword volatile to the flag variables in the programs BadCSFlag, Bakery2, SoSoCSTurns, and unused/TieBreaker. No change is needed to the generalform program. We did not make changes to unused/TieBreakerN or BakeryN programs since those involve arrays (but see the sharedvars/README for how one might do so). Other programs in the book don't need volatile since they use JR synchronization, which cause shared variables to be updated as desired.

The need for this change was first observed with jdk1.6.0_16 on a dual-processor and on a multi-core. (The SoSoCSTurns program would sometimes hang.) Apparently, this implementation is more aggressive than previous ones.

We updated the JR book code extracts in the current version (2.00602). (These changes will be carried forwarded in subsequent versions.)