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Newsgroups: comp.os.386bsd.questions Path: sserve!newshost.anu.edu.au!munnari.oz.au!news.Hawaii.Edu!ames!agate!doc.ic.ac.uk!uknet!mcsun!chsun!hslrswi!aut!nbladt From: nbladt@autelca.ascom.ch (Norbert Bladt) Subject: [SUMMARY] FreeBSD: Does it solve the 16M problem Message-ID: <CD4K3r.zC@autelca.ascom.ch> Organization: Ascom Autelca AG, Guemligen, Switzerland References: <g89r4222.747163756@kudu> <26itba$eaj@pdq.coe.montana.edu> <CD2qLA.vq@autelca.ascom.ch> <JKH.93Sep9162315@thrush.lotus.com> Date: Fri, 10 Sep 1993 06:16:39 GMT Lines: 101 jkh@thrush.lotus.com (Jordan K Hubbard - he's back again) writes: >>So, is it OK to use addresses higher than 16MB for DMA on an EISA system ? >Just so long as you're using a DMA using disk controller in EISA mode, >rather than ISA mode, yes - it will. >For those who may find such a distinction confusing, let me explain: >You can use an ISA controller (such as an Adaptec 1542) in an EISA >machine, but as it will still think it's in an ISA box and refuse to >use the extra address lines, this is no different than having an >ISA machine as far as >16MB is concerned. >You can use an EISA controller in "ISA mode", meaning it uses the >older protocols for compatability reasons (examples being Adaptec 1742 >in "standard" mode, DTC 3290 in "Adaptec" mode, etc) and again, does >not use the extra address lines. >The only way to get full EISA, 32MB-of-memory-and-everything, mode is >to use an EISA controller in full EISA mode (for Adaptec 1742, this >is "enhanced" mode, for DTC 3290 it's "DTC" mode). >FreeBSD (and NetBSD) currently support the Adaptec 1742 in enhanced >mode. I don't think there is any other combination that will get you >more than 16MB in an EISA machine at the moment. Thank you very much for this clarification. I did not find this hint (you have to use the enhanced mode of the 1742 to use the EISA 32-bit bus for DMA) in the Adaptec manual. I am using it in standard mode, now. The only reason is that 386BSD couldn't boot if the controller was in enhanced mode. However, the 1742 is switched to enhanced mode after boot. I received some other answers from David Greenman <davidg@implode.rain.com> and osyjm@schizo.coe.montana.edu (Jaye Mathisen) Both said they are using or used a system with up to 64 MB of RAM and it worked. Thanks again for all the answers I received. Norbert. P.S. Here are the other replies I did receive: ------------------------------------------------------------------------------- From: David Greenman <davidg@implode.rain.com> Reply-To: davidg@implode.rain.com Date: Thu, 09 Sep 93 01:39:21 -0700 Sender: root@corbin.rain.com Content-Length: 545 X-Lines: 13 >Then, is it correct, that there is no bus (EISA or ISA) dependant part >in the kernel (except for the EISA drivers, of course) ? > >So, is it OK to use addresses higher than 16MB for DMA on an EISA system ? > >I am wondering whether adding another 8MB to my 16MB EISA machine will work. >It seems to me it should but I can't believe that there is no dependancy >on the bus used. Or is it handled by the kernel somewhere ? I have 32MB of memory in my adaptec 1742A controller based machine. ...and of course I'm running FreeBSD-1.0-GAMMA. -DG ------------------------------------------------------------------------------- From: osyjm@schizo.coe.montana.edu (Jaye Mathisen) To: nbladt@autelca.ascom.ch Subject: Re: FreeBSD: Does it solve the 16M problem Newsgroups: comp.os.386bsd.questions References: <g89r4222.747163756@kudu> <26itba$eaj@pdq.coe.montana.edu> Organization: Computer Science, MSU, Bozeman MT, 59717 Cc: Content-Length: 809 X-Lines: 20 In article <CD2qLA.vq@autelca.ascom.ch> you write: >nate@bsd.coe.montana.edu (Nate Williams) writes: > >So, is it OK to use addresses higher than 16MB for DMA on an EISA system ? > >I am wondering whether adding another 8MB to my 16MB EISA machine will work. >It seems to me it should but I can't believe that there is no dependancy >on the bus used. Or is it handled by the kernel somewhere ? No, you can put more memory in there on the EISA box, I had 64MB on mine with no problems. there's only 24 lines for address on the ISA which is 16MB (2^24), but the EISA box has 32 lines for address, so it's not a problem. Go crazy. -- Jaye Mathisen, COE Systems Manager (406) 994-4780 410 Roberts Hall,Dept. of Computer Science Montana State University,Bozeman MT 59717 osyjm@cs.montana.edu ------------------------------------------------------------------------------- -- Norbert Bladt, Ascom Autelca AG, Worbstr. 201, CH-3073 Guemligen, Switzerland Phone: +41 31 999 65 52 FAX: +41 31 999 65 44 Mail: nbladt@autelca.ascom.ch UUCP: ..!uunet!mcsun!chsun!hslrswi!aut!nbladt