Date: Tue, 01 Jul 1997 15:43:07 -0700 From: Julian Elischer <julian@whistle.com> To: "Gary D. Margiotta" <gary@tbe.net> Cc: Gennadi Makhmetov <gena@ph-elec.phys.msu.su>, freebsd-hardware@FreeBSD.ORG Subject: Re: lnc device Message-ID: <33B987FB.FF6D5DF@whistle.com> References: <Pine.BSF.3.95q.970701164038.668B-100000@lightning.tbe.net>
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Gary D. Margiotta wrote: > > > if you can get a NON PCI MB. just use 16 bit SMA/WD cards. > > (they are also cheaper). > > do NOT use NE2000 cards. > > Just out of curiosity, do you mean generic NE2000 cards, and if so, may I > ask as to why you say not to get them. We have a few NE2000 generic cards > in some machines here, and have absolutely no problems with them, plus > their speeds aren't bad. They aren't near as good as the Intel Pro100B > PCI cards we also use, but they are still decently fast nontheless... > > -Gary Margiotta > TBE Internet Services > http://www.tbe.net they use programmed IO which on most Motherboards is 1uSec per 16 bit read the shared memory cards can be as low as 250nSec per 16 bit read given good MBs and are more typically in the 500nS per read.. 1 ethernet @10Mb/sec requires 600K reads per sec at 1uSec per read, that's 0.6 of a second for 1Sec's data if you have 2 cards (e.g. a router) that's 1.2 Secs per secon's data so obviously you lose packets. on a bad MB you can't even use 2 shared memory cards, because bad (read ALI) motherboards slow down the ram cycles to almost 1uSec as well.
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