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Newsgroups: comp.os.386bsd.questions Path: sserve!newshost.anu.edu.au!munnari.oz.au!spool.mu.edu!uwm.edu!news.moneng.mei.com!hookup!olivea!uunet!ncrgw2.ncr.com!ncrhub2!ncrcae!news From: john dyson <dyson@root.com> Subject: Re: *BSD and 115kbps Serial Message-ID: <D1zqoI.KIA@ncrcae.ColumbiaSC.NCR.COM> Sender: news@ncrcae.ColumbiaSC.NCR.COM (news) Reply-To: dyson@root.com Organization: Company, Address X-Newsreader: DiscussIT for Windows (1.8.6) [Software Products Division of AT&T/NCR] References: <3eegop$3r9@homer.alpha.net> <JBH.95Jan5100037@moses.oau.org> Date: Fri, 6 Jan 1995 15:50:42 GMT Lines: 31 >In article <JBH.95Jan5100037@moses.oau.org> James B. Huber writes: > > Can't speak for FreeBSD, I run BSDI ver. 1.1 I've been complaining >bitterly about how bad the serial performance is. It is NOT capable >of running 38.4k with 16550's. It silo overflows all over the place, >the only option for me was to hack the driver myself. I've got it >to run 38.4k now, but BSDI won't bless it. Not only that, they >aren't going to fix it either. > It still isn't up to 57.6k, it appears that the interrupt latency >on the O/S is disgustingly high. Perhaps their version 2.0 will >improve it, perhaps FreeBSD is better. > The "Free" BSDs (NetBSD, FreeBSD) both support a *very* efficient "software" DMA scheme for I/O devices. They can easily sustain at least one 115K link (on faster PCs). People are succesfully using more that that too. I think that Linux has the same kind of scheme... John Dyson (FreeBSD core team) dyson@root.com