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To: Nate Williams <nate@mt.sri.com>, Charles Henrich <henrich@crh.cl.msu.edu>
cc: freebsd-hackers@FreeBSD.ORG
From: "Louis A. Mamakos" <louie@TransSys.COM>
Subject: Re: tty-level buffer overflows 
References: <19970803025730.57257@crh.cl.msu.edu> <199708030852.SAA13473@genesis.atrad.adelaide.edu.au> <19970803112147.21483@crh.cl.msu.edu> <199708040423.WAA26367@rocky.mt.sri.com> 
In-reply-to: Your message of "Sun, 03 Aug 1997 22:23:17 MDT."
             <199708040423.WAA26367@rocky.mt.sri.com> 
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Date: Mon, 04 Aug 1997 01:11:36 -0400
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> > > Your application is busted; data is arriving faster than your app is reading
> > > it, and the kernel has run out of patience and started throwing the data
> > > away.
> > 
> > Im afraid not, the application is a software Upload, with a singly byte ack
> > every 2k, if the serial port cant handle that, theres a problem.  I would
> > presume that if the buffer is full, a write() should block.  
> 
> You've got a 16 byte FIFO, and you're wondering why it's overflowing
> when your application is trying to get 2K at a time?  You've *GOT* to be
> kidding, right?

No, I think that Charles is surprised that he's *sending* 2K blocks,
and getting error messages described on the single byte ACK characters
which is being *received*.

Could it be that there is cross-talk, and some of the data being transmitted
is being "heard" as input?

louie