Date: Fri, 5 Jul 1996 20:36:58 +1000 From: Bruce Evans <bde@zeta.org.au> To: bde@zeta.org.au, stesin@elvisti.kiev.ua Cc: hardware@freebsd.org, isp@freebsd.org Subject: Re: muliport boards - building a PPP dialup server Message-ID: <199607051036.UAA00165@godzilla.zeta.org.au>
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> So an idea to get a PCI board seems to be pretty reasonable... If the PCI interface is actually faster. > Anyway, ISA is a dead-end, I think. (Consider the following: > 16 ports seems to be an upper limit for ISA card at 8MHz, even if > it's 16bit "smart" one -- simply because it's ISA. > PCI has 33Mhz => 4 times faster, > it's a 32bit bus => add two times more. So PCI intellgent Only for 32bit peripherals. Not for 8-bit peripherals like 16550s and cd1400s. These have at most 1/2 the bandwidth of the ISA bus because they use only 1/2 its width. In practice they usually have only 1/5 the bandwidth of the ISA bus because they don't support insb/outsb. > card should be able to handle at least 8 times more ports > at full speed, => up to 128 ones! And just today I have The software overhead would be too large for more than 32 or 64 * 115200 bps on a Pentium. Fortunately, modems can't sustain 115200 bps. Bruce
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