7.2   Cons of PVM

• Low level package. PVM lacks high level facilities such as
  • Fault tolerance
  • Process migration...
• Distributed I/O is not supported
• No support for
  • Shared memory
  • Data mapping
  • Data distribution
  • Data replication
• Security relies entirely on Unix based security techniques
  No support for data encryption for example
• No load balancing
  But a load balancing package is under development

• Scalability issues
  • Broadcast are realized in a linear fashion
    Hardware multicast is not used
  • Local communications are linearized though the daemon process
  • On a large virtual machine (>10, 20 hosts): multiplication of the daemon processes
• Basic trace/debugger facilities
• No performance monitoring
• Support is (was ?) a problem since PVM is a public domain comp.parallel.pvm news group