Problems with 4.2 lpd flow control

deb at gt-eedsp.UUCP deb at gt-eedsp.UUCP
Fri Feb 20 02:01:51 AEST 1987


System config:  4.2BSD(BRL) running on a Vax 11/780; DMF32 Mux's

Has anyone ever seen a flow control problem between their tty lines
and printers?  We've got a laser printer connected via an rs232 cable
to a dmf32 serial port with modem control.  It refuses to recognize
^S/^Q coming from the laser printer.  We know it's being sent since
it works on our DG MV10000.  Flow control works on the port when we
have getty running on it, so it's not a hardware problem.  My guess is
that the proper ioctl calls are not being made, so here's the real
question:  What should I have in /etc/printcap?

Here's my printcap: (well, most of it, the fs/fc and xs/xc entries
are the important ones, right?)
	canon|Canon|Canon Laser printer:\
		:lp=/dev/ttyh9:br#4800:\
		:fs#00321:\
		:xs#040000:xc#030000:\

The only problem we're having is the flow control.  After looking at the
printjob routine called by lpd, and running some tests, I know that it
gets to the ioctl calls that send these parameters, but I don't know if
they're having any effect.  Unless there's something inherently wrong
with lpd, I don't want to hack at it, but I'd like to avoid writing a
separate spooler.  Since we're using the Canon to print TeX dvi files,
they're usually fairly large files, and even with a buffer we can't print
more than 17 pages at a time without data overrun.

Any help will be much appreciated.

-Deb Jackson
-- 
Georgia Tech, School of Electrical Engineering, Atlanta, GA 30332
(404)894-3058
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