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Received: by minnie.vk1xwt.ampr.org with NNTP id AA1578 ; Tue, 23 Feb 93 14:49:18 EST Path: sserve!manuel.anu.edu.au!munnari.oz.au!news.Hawaii.Edu!ames!olivea!sgigate!sgiblab!rtech!amdahl!JUTS!zombie!tjw00 From: tjw00@zombie.NoSubdomain.NoDomain (Tom Wye) Newsgroups: comp.unix.bsd Subject: Re: 386BSD Machine Configurations > 16Megabytes Message-ID: <92r702cX36Nv01@JUTS.ccc.amdahl.com> Date: 18 Feb 93 01:22:26 GMT References: <C2E7KL.1sx@acsu.buffalo.edu> <JKH.93Feb13170535@whisker.lotus.ie> Sender: netnews@ccc.amdahl.com Lines: 39 In article <JKH.93Feb13170535@whisker.lotus.ie>, jkh@whisker.lotus.ie (Jordan K. Hubbard) writes: |> In article <C2E7KL.1sx@acsu.buffalo.edu> jones@acsu.buffalo.edu (T. Jones) writes: |> |> I have seen this question posed before but do not recall seeing |> any definitive responses. I wanted to know what it would take to configure |> an ISA machine running 386BSD with greater than 16 meg of memory and a |> 1542 host adapter. Is the issue of DMA addressing beyond the 16 meg limit |> (bounce buffers) handled by Julian's SCSI driver? If not, what would it |> take? |> |> Julian's drivers won't handle this. You'd need to implement some sort |> of copy-down scheme to make sure the DMA buffers were in the lower 16MB. |> |> 386bsd doesn't adequately use memory >16MB anyway, so I'd say that your |> price/performance ratio isn't worth purchasing an extra 16MB if it's |> just to get better performance out of 386bsd, at least not for now. |> I had this same problem when I installed 386BSD on my 486/50 with 20 megabytes installed. UNFORTUNATELY after spending a few days with the system crashing and burning REAL badly some kind soul answered my posting pointing out this problem. This would be a nice problem to write up in a OFFICAL 386BSD FAQ if there is never one produced! By the way other than that problem and a few other problems I have had, I think 386bsd is great! THANK YOU all who have made it possible. I have trashed by copy of SCO UNIX which by the way supported >16M and the 1542 host adapter. Also in the past someone had posted that they put in the support for >16M put performance was poor so they did not release the patches. Any news why performance went to hell? PS: I have pulled out the 4M and put it on the shelf waiting for the day when the 386BSD SCSI driver supports it!