On Sat, 04 May 1996 10:54:25 -0400 
 "Perry E. Metzger" <perry@piermont.com> wrote:

 > I believe that having a 1k FIFO on the serial card helps
 > dramatically. Most people, sadly, have no such option. The incremental
 > cost in PC hardware might be pennies, but no one makes the things
 > standard equipment anyway...

...well, I talked to Herb a great deal when he was working on the serial 
problem he's referring to...he indicated that without the TTYHOG change 
and larger ring buffers, even his ESP was having problems at such high 
speed.

Really, what these changes lessen is the case where the driver is getting 
the data off the card, but ends up having to drop it on the floor because 
there's no more room left in the tty ring buffer (because the process or 
other reader hasn't been given a chance to run yet) ... kind of like a 
form of livelock, but not quite.

----save the ancient forests - http://www.bayarea.net/~thorpej/forest/----
Jason R. Thorpe                                       thorpej@nas.nasa.gov
NASA Ames Research Center                               Home: 408.866.1912
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