Date: Sun, 30 Jun 1996 01:06:38 +0930 (CST) From: Michael Smith <msmith@atrad.adelaide.edu.au> To: jparnas@jparnas.cybercom.net (Jacob M. Parnas) Cc: msmith@atrad.adelaide.edu.au, stesin@elvisti.kiev.ua, Kevin_Swanson@blacksmith.com, hardware@freebsd.org, bsdi-users@bsdi.com Subject: Re: muliport boards - building a PPP dialup server Message-ID: <199606291536.BAA21513@genesis.atrad.adelaide.edu.au> In-Reply-To: <199606291523.LAA07860@jparnas.cybercom.net> from "Jacob M. Parnas" at Jun 29, 96 11:22:54 am
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Jacob M. Parnas stands accused of saying: > > Thanks for the information. But as I said in a recent message, the new TI > chip can go over 900Kbaud/sec. This isn't so fast. Its 1/10th the speed > of old ethernet and 1/100 of new 100 Mbit/sec ethernet. As I've already said, the 16550 will go faster. The problem is that the programming model for the 16550 makes no provision for more divider steps, and thus any software that wants to talk to either of these chips must be modified to understand the higher speeds. Quatech do a card called the DS-100 with a pair of PC16550D's and an 18MHz clock and a jumperable /1 /2 /5 /10 divider that will allow your to run your 16550 ports significantly faster. Unfortunately, they tried to implement the card properly, and as such we have had serious problems with the cards in fast (>486/33) machines. > I understand, but it still seems funny that a computer shipped in 1990 or so > (The IBM RT running BSD and with the enhanced advanced processor), couldn't > put up to date UARTS on the motherboard UARTS or 4 port card uarts, and get > it working fast and reliably. I think the one on the motherboard had 1 or 2 > bytes of buffering. Serial ports like that are intended as console ports or for debugging the system during development. Standard network design philosphy does not allow for compute servers to have heavy I/O. Look at the Encore Multimax for a good example of this; lots of compute, lots of disk & memory, but Encore built its serial I/O into a seperate box and called it an Annex. > The costs are $68 for my line install (cheaper, I think than my > analog second line) $25-35/month telco (about same as analog) about > $60 vs $20 for analog for unlimited usage. $.01/min/channel > (biggest problem. In southern CA, I have a friend who doesn't the > surcharge per minute on weekends and I think northern CA may be even > cheaper. $400 for "modem/terminal adapter" and Unix driver. (may be > lower in some places. Your americocentricity is appalling. In most of the civilised world, ISDN is still outrageously expensive. > I prefer to be able to get a contracted support policy, which I don't think > FreeBSD has. Therefore, I'm going with BSDI. I'd rather not be down for > a long time because of maintainer of a piece of code is on vacation for 3 > weeks. BSDI has a paid for support contract which requires them to fix > things promptly for not much money. You should try talking to Karl Denninger (or perhaps just read his posts to the various FreeBSD lists) before you make the choice. Search for karl@mcs.net (or just mail him and ask). > After being burned by it once, I've been careful since to avoid such problems. Your naivete' is touching. > >> | Jacob M. Parnas -- ]] Mike Smith, Software Engineer msmith@atrad.adelaide.edu.au [[ ]] Genesis Software genesis@atrad.adelaide.edu.au [[ ]] High-speed data acquisition and (GSM mobile) 0411-222-496 [[ ]] realtime instrument control (ph/fax) +61-8-267-3039 [[ ]] Collector of old Unix hardware. "Where are your PEZ?" The Tick [[
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