cat /dev/ttya > /dev/null &

[David B. Pointer]

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

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