Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Posting-Version: version B 2.10.2 9/18/84 SMI; site sun.uucp Path: utzoo!linus!decvax!decwrl!sun!guy From: guy@sun.uucp (Guy Harris) Newsgroups: net.bugs.uucp Subject: Re: One-second break is too long Message-ID: <2795@sun.uucp> Date: Fri, 13-Sep-85 20:36:50 EDT Article-I.D.: sun.2795 Posted: Fri Sep 13 20:36:50 1985 Date-Received: Sun, 15-Sep-85 05:03:48 EDT References: <24@pyramid.UUCP> Organization: Sun Microsystems, Inc. Lines: 17 The original V7 code for transmitting breaks did so by setting the speed to some strange value and writing a pile of NULs. This was because the V7 TTY driver didn't give you access to the break-generation hardware that was in the PDP-11s (and lots of other machines') terminal muxes. The S3, S5R1, and S5R2 code just does a TCSBRK system call which turns on the mux's break bit for 1/4 sec and then turns it off again. S5R2V2 may do it differently (I don't have the source handy). 4.1BSD and 4.2BSD have no call to send a timed break; they just have the ability to turn the break bit on and off. I suspect the code for the 4.2BSD UUCP may be a mix of the V7 code and code that used TIOC[SG]BRK. The way it's written there may be a historical dreg. OK, Peter, what does honey danber do? Guy Harris