Path: utzoo!attcan!uunet!know!zaphod.mps.ohio-state.edu!rpi!uupsi!sunic!news.funet.fi!tukki.jyu.fi!jyu.fi!otto From: otto@tukki.jyu.fi (Otto J. Makela) Newsgroups: comp.dcom.lans Subject: Re: 3com ethernetcard + SCO TCP/IP Message-ID: Date: 16 Oct 90 14:52:14 GMT References: <27886@bellcore.bellcore.com> Sender: news@tukki.jyu.fi (News articles) Organization: Turing Police, Criminal AI section Lines: 43 In-Reply-To: louie@cellar.bae.bellcore.com's message of 15 Oct 90 18:35:31 GMT In article <27886@bellcore.bellcore.com> louie@cellar.bae.bellcore.com (Paul Louie) writes: By setting the IRQ5 you've conflicted with the floppy controller. Each machine can use IRQs differently, but the industry's practice has been: IRQ1 - timer IRQ2 - Whatever, according to the manufacturer IRQ3 - COM2 IRQ4 - COM1 IRQ5 - Floppy IRQ6 - LPT2 IRQ7 - LPT1 IRQ9-13 - Whatever, according to the manufacturer IRQ14 - HD Controller IRQ15 - Again, whatever. The list above is INCORRECT for a standard PC/AT, here are the correct values: IRQ0 Timer interrupt (18.2 times a second) IRQ1 Keyboard IRQ2 EGA vertical retrace - rerouted to IRQ9 on AT machines IRQ3 COM2 IRQ4 COM1 IRQ5 LPT2 IRQ6 Floppy IRQ7 LPT1 Note that IRQ2 from the bus is routed to IRQ9 on AT machines, but on MS-DOS you normally don't see it since IRQ9 calls the IRQ2 handler. On Unix, you do see a difference :-) Unless you have EGA, you needn't worry about this being used. You can see from the above that EISA is a good idea with it's interrupt sharing. Often one *has* to use 16-bit cards just for the extra IRQs available. As you can see, IRQ5 is about the only one available within the 8-bit interrupt limits that normally isn't used (most machines nowadays come with two COM ports and one LPT, but I've yet to see machines with two LPTs on the motherboard). -- /* * * Otto J. Makela * * * * * * * * * * * * * * * * * * */ /* Phone: +358 41 613 847, BBS: +358 41 211 562 (CCITT, Bell 24/12/300) */ /* Mail: Kauppakatu 1 B 18, SF-40100 Jyvaskyla, Finland, EUROPE */ /* * * Computers Rule 01001111 01001011 * * * * * * * * * * * * * * * * */