Date: Sat, 6 Apr 1996 04:26:33 +1000 From: Bruce Evans <bde@zeta.org.au> To: bde@zeta.org.au, jgreco@brasil.moneng.mei.com Cc: current@FreeBSD.ORG, root@deadline.snafu.de Subject: Re: tty-level buffer overflows - what to do? Message-ID: <199604051826.EAA18166@godzilla.zeta.org.au>
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>> >What kind of drives? IDE drives bite, particularly if they are being used >> >at the same time as the serial port... etc, etc. >> >> IDE drives have no affect on the operation of the serial unless they >> are so slow that the system spends too much of its time in the kernel. >> Bus-hogging SCSI controllers bite. >It has been my observation that IDE drives DO tend to affect the operation >of serial I/O, at least during heavy I/O periods. Small-memory systems tend >to spend much more time doing "heavy I/O" (swapping), in my experience, this >is just one reason I put 8MB in even my smallest machines these days. It's an indirect effect. Small-memory systems are more likely to have slow IDE drives that make the swapping slower. You probably can't afford to swap the applications doing serial i/o at all if you don't use flow control - the kernel buffers are only large enough for 100 msec of input at 115200 bps. Bruce
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