Date: Thu, 4 Apr 1996 12:12:03 -0700 From: Nate Williams <nate@sri.MT.net> To: Joe Greco <jgreco@brasil.moneng.mei.com> Cc: root@deadline.snafu.de (Andreas S. Wetzel), current@FreeBSD.org Subject: Re: tty-level buffer overflows - what to do? Message-ID: <199604041912.MAA17250@rocky.sri.MT.net> In-Reply-To: <199604041821.MAA01616@brasil.moneng.mei.com> References: <m0u4svg-0009vMC@deadline.snafu.de> <199604041821.MAA01616@brasil.moneng.mei.com>
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> > The serial ports used on the modems are all of type 16550A. RTS/CTS flow > > control is hardwired for all modem lines. The machine has one dedicated > > slip line as well as two dialup ports attached to it. The syslog messages > > all seemed to related to the first dialup port which is a V34+ modem operated > > at 115k2 bps. The mgetty on the dialup ports is configured to do a direct > > rlogin onto another FreeBSD machine for all logins, so it just hands off > > the dialup connections. > > My gut instinct is that you would find a correlation between your IDE disk > going and these error messages. A 486/40 should be adequate, even for > several lines at 115200. The fact that you are tight on memory would tend > to cause you to hit the disk correspondingly more often, which would cause > some burps in serial I/O... the fact that you're running rlogin also would > tend to cause you to swap more, if you have a few active sessions. One of > the nice things about kernel-mode SLIP is that no paging is involved.... > That's possible, but let me throw in another data point. 486/66 - 16MB memory 3 16550 UART serial lines - 115K 540MB IDE drive With 2 lines going full blast (sup updates!) I see *NO* overflows on my box. Again, my box is running with about 6MB of free memory all the time, so I rarely hit the disk, but I've done compiles on the machine to upgrade software with no noticeable degradation of serial speed. However, I do no paging at all, so my disk is mostly idle even during compiles. Nate
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