Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Path: utzoo!mnetor!seismo!rutgers!ames!ucbcad!ucbvax!sdcsvax!brian From: brian@sdcsvax.UCSD.EDU (Brian Kantor) Newsgroups: comp.bugs.4bsd Subject: Re: TANDEM mode bugs in 4.3bsd Message-ID: <2439@sdcsvax.UCSD.EDU> Date: Sat, 10-Jan-87 09:36:55 EST Article-I.D.: sdcsvax.2439 Posted: Sat Jan 10 09:36:55 1987 Date-Received: Sat, 10-Jan-87 22:42:43 EST References: <973@tymix.UUCP> Reply-To: brian@sdcsvax.UCSD.EDU (Brian Kantor) Distribution: world Organization: UCSD wombat breeding society Lines: 26 In article <973@tymix.UUCP> feldman@tymix.UUCP (Steve Feldman) writes: >Description: > There are two problems in the TANDEM mode handling in the > 4.3 bsd tty driver. (They were in 4.2 as well.) > > First, if you have a device which is slow responding to > a control-S, the driver can send additional control-S's > when the last few characters arrive. This may not be a bug, depending upon how you view it. It is ALSO possible for the remote device to lose the XOFF character which means that you MUST send it again or it will NEVER stop. Very very few devices queue an incoming XOFF, which means that extra ones don't hurt and are likely more often to help. Conjecture: What may have prompted this is using terminal i/o with TANDEM set to communicate with some other computer system which does not obey the same XOFF/XON semantics as Unix does. CP/M systems, for example, use XOFF to stop output, but will restart it again on ANY character, including another XOFF. In this situation, the behaviour of TANDEM is not optimal. But the real solution may be to fix the remote host/device. Brian Kantor UCSD Office of Academic Computing Academic Network Operations Group UCSD B-028, La Jolla, CA 92093 USA