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Path: euryale.cc.adfa.oz.au!newshost.anu.edu.au!harbinger.cc.monash.edu.au!news.mel.connect.com.au!munnari.OZ.AU!news.hawaii.edu!ames!usenet.kornet.nm.kr!news.kreonet.re.kr!news.dacom.co.kr!newsrelay.netins.net!solaris.cc.vt.edu!hookup!tank.news.pipex.net!pipex!swrinde!news-relay.us.dell.com!news-relay.us.dell.com!not-for-mail From: james@raid.us.dell.com (James R. Van Artsdalen) Newsgroups: comp.unix.bsd.bsdi.misc Subject: Re: multiple pci cards [shared IRQs] Date: 10 Mar 1996 19:34:58 -0600 Organization: Dell Computer Corporation Lines: 22 Message-ID: <4i0002$qg@raid.us.dell.com> References: <313E5821.6D78@execpc.com> <4htrn1$otm@raid.us.dell.com> <4hve6j$1c0@park.uvsc.edu> Reply-To: james@raid.us.dell.com (James R. Van Artsdalen) NNTP-Posting-Host: raid.us.dell.com In <4hve6j$1c0@park.uvsc.edu>, Terry Lambert <terry@lambert.org> wrote: > Now just because something is allowable, doesn't mean it is > preferrable. In point of fact, you will probably get higher > performance on a system where you do not need to demux the PCI > interrupts Some PCI cards share IRQs in hardware, on the card. There is no opportunity for an enterprising BIOS to demux them. A card with a PCI-PCI bridge often has several chips with interrupt capability behind it (multi-channel NIC or SCSI). Many of these cards are designed to only assert a single PCI INT on the system PCI bus. I can't think of a specific example off the top of my head. But I believe that either Znyx or Adaptec sell such cards: Zynx may a board with four DEC 21040's sharing one INT, or Adaptec's 3940-class cards with two or three 78x0 chips may share an INT. I forget which. -- James R. Van Artsdalen james@dell.com "Live Free or Die" Dell Computer Co 9505 Arboretum Blvd Austin TX 78759-7299 512-728-8789