Xref: utzoo unix-pc.general:2756 unix-pc.uucp:105
Path: utzoo!utgpu!watmath!uunet!lll-winken!scooter!neoucom!wtm
From: wtm@neoucom.UUCP (Bill Mayhew)
Newsgroups: unix-pc.general,unix-pc.uucp
Subject: Re: Hardware flow control on tty000?
Summary: /etc/hfc_ctl
Message-ID: <1565@neoucom.UUCP>
Date: 6 Apr 89 01:15:54 GMT
References: <1298@naucse.UUCP>
Organization: Northeastern Ohio Universities College of Medicine
Lines: 24


/etc/hfc_ctL +/dev/tty000  turns it on.

/etc/hfc_ctl -/dev/tty000  turns it off.

This is documented for version 3.51 in The Unix System V Users
Manual Volume I.  It is in the addendum section in the back.  There
are a number of interesting things in the addendum that are easily
over looked.  Be sure to check it out.

You could probably issue an ioctl call from a c program too.  One
thing to watch out for is that the port hangs if you issue the
ioctl while it is active.  I found out when I put an /etc/hfc_ctl
in my .profile that it would always lock up the line dialing in.
It doesn't seem to mind if you type it in from the shell prompt
while logged in over tty000; in that case the flow control changes
properly without incicent.

Also note that if you enable hfc via /etc/hfc_ctl, the kernel stops
doing software flow control; a pain for things that want to show
you more than 24 lines of stuff, but not one screen at at time and
you want to type ^S.

Bill