Date: Tue, 11 Jul 1995 18:32:05 -0400 From: dennis@et.htp.com (dennis) To: "Rodney W. Grimes" <rgrimes@gndrsh.aac.dev.com> Cc: freebsd-hackers@freebsd.org Subject: Re: Wanted: 100bT EISA ethernet recommendation Message-ID: <199507112232.SAA10221@mail.htp.com>
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R. Grimes writes..... >> >EISA has a bus bandwidth of 33 mega*bytes* per second. >> > >> OK. I'll bite. Obviously my spec sheet is old/wrong or I don't get the new >> math. The orginal EISA spec was 8.3mhz / 32 bits with 4-6 cycle access. This >> is 88mbs best case with a real expectation of a little better than 60mbs >> actual xfer capability. The knock on EISA has always been that its not that >> much faster than ISA so this 32MB/s stuff must be new. > >You completely ignored bus master DMA which is 1 32 bit word per cycle or >33MB/sec. Your looking at PIO data rates, not DMA rates. > That's 'cause the EISA spec I have doesn't have.any such thing. It only has Type A and Type B transfers. Type C must have come later.....what's that date on this stupid thing?!...... I guess the updated answer would be....make sure the card does Type C transfers otherwise its too slow..... db
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