8.1   New features of PVM 3.4

• Context
  • Problem:
    • Use of a Math Lib using PVM in a PVM application.
    • A math routine may intercept a user message !
  • Solution : communication context
    • Additional tag associated with messages
    • Generated by the system at execution time
  
  
• Data encoding
  • Was XDR
  • Will be RMR: Receiver Makes Right
  • Avantages:
    • At most one conversion on any message
    • XDR only defined for 32 bit words
  • Drawbacks:
    • Each receiver must be able to decode every other format
• Buffered Tracing
  • Þ Update of XPVM

• Name service
  • Goal
    • Two PVM programs start independently
    • And discover information about each other
  • Use of a ``name server''
    • Database managed by PVM
  
  
• Static groups
  • Presently : dynamic group
    • Members can join and leave asynchronously
    • Cost of performance: PVM uses a central group server
      Þ Bottleneck
  • Add static groups
    • Members of the group can never change once the group is formed
    • Created synchronously
      • List of tids

• MPI/PVM and PVM/MPI
  • MPI Forum: Standard specification for message-passing
  • PVM: de facto standard for distributed computing
  • Question: will MPI and PVM merge?
  • The PVM development team will not change the PVM API
    • Obligation to the PVM community
    • PVM API has evolved based on needs and requests from users
    • PVM API simple and easy to learn and use
  • MPI API?
    • Good design for MPP
    • For network of workstations: lacks features (process control...)