VMWare serial ports

serialvirtualizationvmware-esxivmware-servervmware-workstation

Can someone tell me the difference between the different ways virtual serial ports can be configured using VMWare Infrastructure?

For instance:

  • What is the difference between "use output file" and "use named pipe"?
  • Can "Use Output File" be used to connect 2 machines?
  • When using a "named pipe", can that just be an arbitrary fifo on the shared SAN? Does it need to be created in advance, or will vmware create it as needed?
  • When using a "named pipe", I assume one server needs to be configured as "server" and the other as "client", and that it doesn't matter which one is which – is that correct?
  • What does "Yield on CPU poll" mean – and which mode is better for a constant serial port connection?

Thanks

Best Answer

  • A Named pipe virtual serial port behaves more like a traditional
    serial port - with both input and output, while an 'Output file' is
    mostly useful for quickly capturing program output to a file.
  • An "Output file" would not be useful for bidirectional communication between machines.
  • The actual name of the named pipe is declared in the setup for the virtual machine.
  • The selection of which named pipe is the server and client does not matter; a client can only connect to a server.
  • "Yield on CPU poll" applies to special applications which communicate with the serial port by polling. Kernel debuggers are an example; when blocked while debugging an interrupt, no further interrupts can be reliably processed. This setting would not apply to typical inter-machine connections over named pipe serial ports.
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