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Path: sserve!newshost.anu.edu.au!munnari.oz.au!bunyip.cc.uq.oz.au!s1.elec.uq.oz.au!clary From: clary@s1.elec.uq.oz.au (Clary Harridge) Newsgroups: comp.os.386bsd.questions Subject: DMA beyond end of ISA with Adaptec 1542 and 32MB memory Date: 9 Dec 1993 06:54:54 GMT Organization: Dept. of Elec. and Comp. Engineering, Uni of Queensland Lines: 20 Distribution: world Message-ID: <2e6i3u$evt@bunyip.cc.uq.oz.au> Reply-To: clary@s1.elec.uq.oz.au NNTP-Posting-Host: s3.elec.uq.oz.au Keywords: DMA ISA Adaptec 1542 I am running FreeBSD on a 486 DX2-50 with a Adaptec 1542 SCSI controller. I get the error "DMA beyond end of ISA" from the aha1542 driver when I install 32MB of memory. As the ISA bus device can only address 16MB of memory, the DMA transfer error is caused when attempting I/O to the top 16MB of memory. Is there some configu switch or driver modification which will ensure the driver won't attempt DMA to the top 16MB of memory? OR Do I have to buy a machine and controller with 32bit I/O slots if I want to have more than 16MB of memory? -- regards Dept. of Electrical Engineering, Clary Harridge University of Queensland, QLD, Australia, 4072 Phone: +61-7-365-3636 Fax: +61-7-365-4999 INTERNET: clary@s1.elec.uq.oz.au