[PLUG] Re: dynamic file (script output)

[Kevin Falcone <kevinfal@seas.upenn.edu>]

>>>>> "Md" == MaD dUCK <madduck@madduck.net> writes:

  Md> but would i then not be filling up the FIFO to the point of no
  Md> return??? how is a FIFO stored? in memory?

/usr/src/linux/fs/fifo.c for the gory details

  Md> it would be nice to have a FIFO that could act as a "packet
  Md> buffer" of length 1, where i define a packet to be something
  Md> like the output from one invocation. sort of like a super market
  Md> shelf with capacity one: customer service puts product in, then
  Md> only as soon as customer removes the product, a new one is
  Md> placed in.

>From purely empirical evidence, it appears to be a buffer holding one
invocation.  The limit is how fast your daemon can keep refilling it.
Running sigrand, and then cat'ing .signature means that it will block
if sigrand hasn't refilled the FIFO.  Decreasing the time between
loops (or blocking on writing to the pipe) would result in virtually
asynch filling.  

Also, sigrand used to run for days, trying every second to write to
the FIFO, and it didn't fill up ram, so somehow I doubt that it is
caching all of the prints.

-kevin

-- 
"I sense much NT in you. NT leads to Blue Screen, Blue Screen leads to
downtime, downtime leads to suffering. NT is the path to the Dark Side."


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