On 8 Jun 99, at 19:50, Patrick Black wrote:

> There aren't any symptom at all. I was just curious about how I could
> change the size. More specifcally the Maximum size I know how to adjust it
> for DUN, Just can I add more too it to maybe gain a performance
> enhancement.

  The FIFO doesn't really help *performance* directly.  Its main purpose is to
prevent loss of incoming data during the time it may take for the OS to switch
"context" to where it can retrieve the incoming bytes from the port.
  Indirectly, this does also reduce the number of times that such a context
switch must be done, slightly increasing the CPU time available for other
applications.

> Seems to me like there was something added to either win.ini or system.ini.

  I think that's where it was under 3.x, whose default serial drivers didn't
support ports with FIFOs.
  Note that any increase beyond what the port hardware provides (and the
Control Panel lets you configure) would require intervention from the OS --
involving a switch of context as above.  No point in trying to implement such
a thing.  [Windows probably has a way of queuing serial port input until an
application is ready for it, but that would be part of its general
IO/event/message queuing structure and not, so far as I know, something you'd
want a user to be able to tweak.


David G

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