Path: utzoo!attcan!utgpu!jarvis.csri.toronto.edu!mailrus!cornell!uw-beaver!rice!sun-spots-request
From: dpointer@uicsrd.csrd.uiuc.edu (David B. Pointer)
Newsgroups: comp.sys.sun
Subject: cat /dev/ttya > /dev/null &
Keywords: SunOS
Message-ID: <343@brazos.Rice.edu>
Date: 21 Jul 89 13:40:42 GMT
Sender: news@rice.edu
Organization: Sun-Spots
Lines: 23
Approved: Sun-Spots@rice.edu
X-Sun-Spots-Digest: Volume 8, Issue 81, message 13 of 15

I'm running SunOS 4.0.3 on a 3/50. I send a file of HPGL commands to an HP
plotter by " cat filename > /dev/ttya ".  /dev/ttya and the plotter are
configured to use XON/XOFF protocol.  Until recently, the plotter buffer
always overflowed and it appeared that XON/XOFF wasn't recognized by the
3/50.

Now here's the good part.  Our system administrator tells me to have " cat
/dev/tty > /dev/null " running in the background when I want to " cat
filename > /dev/ttya ".  I was a bit skeptical, but I tried the fix, and
it worked.

No one here understands why this fix works. Does anyone on the net have
any ideas why this works?  This really bothers me.  I mean, UNIX at times
seems like black magic, but this looks like REAL voodoo.  Thanks for any
ideas.

*dave

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  David Pointer                    Center for Supercomputing R&D
  dpointer@uicsrd.csrd.uiuc.edu    305 Talbot Lab  104 S. Wright St.
  (217) 244-6392                   Urbana, IL  61801
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