Date: Wed, 21 May 1997 02:39:11 -0400 From: "Gary T. Corcoran" <garycorc@idt.net> To: Bruce Evans <bde@zeta.org.au> Cc: HARDWARE@FreeBSD.ORG Subject: Re: isa bus and boca multiport boards Message-ID: <3382988F.167EB0E7@idt.net> References: <199705210516.PAA05401@godzilla.zeta.org.au>
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Bruce Evans wrote: > On a P5/133, about 300 pointer dereferences can be > done in the time it takes to do one i/o instruction. I know this discussion was concerning I/O ports on the ISA bus, but I'm curious if you know: How long does a single I/O (read or write) take when accessing an I/O port on the PCI bus? I _believe_ that in modern chipsets, for I/O addresses which are supposed to be "PCI only" (higher than a certain address) that the I/O operations do *not* appear on the ISA bus, and thus shouldn't be limited by the ancient ISA I/O speeds - is this true? Thanks, Gary Errr... given all the "Gary's" floating around on these lists, make that: Thanks, Gary Corcoran
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