*BSD News Article 42045


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Newsgroups: comp.os.386bsd.bugs
Path: sserve!newshost.anu.edu.au!harbinger.cc.monash.edu.au!bunyip.cc.uq.oz.au!munnari.oz.au!news.hawaii.edu!ames!agate!howland.reston.ans.net!news.sprintlink.net!news.clark.net!rahul.net!a2i!raw!iverson
From: iverson@lionheart.com (Tim Iverson)
Subject: Re: [FreeBSD 2.0-950112-SNAP] - SIO bug, driver discards chars
References: <D2s65p.AKt@lionheart.com> <3ft7m8$7op@ucthpx.uct.ac.za>
Organization: Lionheart Software
Date: Fri, 27 Jan 1995 11:10:01 GMT
Message-ID: <D329oq.Csn@lionheart.com>
Lines: 27

In article <3ft7m8$7op@ucthpx.uct.ac.za>,
S Marquard <smarq@ucthpx.uct.ac.za> wrote:
>iverson@lionheart.com (Tim Iverson) writes:
>>There is a bug in the SIO driver that causes it to discard characters if
>>the tty is in raw mode and there is no space left in the clist - even when
>>RTS/CTS is enabled.  The SIO man page calls this a bug in the application
>
>Could someone describe this is more "end-user-ish" (:-) terms?
>Under what circumstances does the bug manifest itself? How serious is it?
>Is it likely to affect UUCP transfers, if so how?

I've been corrected - it's not a bug, it's a feature; ie. the SIO driver
doesn't really support flow control, the code just makes it look like it
does.  Yes, it could be a problem for UUCP, but not a big one - it might
cause some packets to be resent.  This is likely only for fast modems and
protocols with large window sizes (eg. i protocol on v.34).

On a 115200 baud direct link, it would discard 400-700 characters every
five or ten minutes.  More chars, more frequently, as the system is loaded.

I'll be fixing this soon - probably Monday if I can find a spare hour or
two.  If I can't guess where to send the patches, I'll probably just post
them to one of the 386bsd groups, like dev or bugs.


- Tim Iverson
  iverson@lionheart.com