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Path: sserve!newshost.anu.edu.au!munnari.oz.au!news.Hawaii.Edu!ames!agate!spool.mu.edu!uunet!pipex!sunic!isgate!veda.is!adam From: adam@veda.is (Adam David) Newsgroups: comp.os.386bsd.questions Subject: Re: Cache testing software. Message-ID: <C5L051.D5t@veda.is> Date: 16 Apr 93 14:55:47 GMT References: <1993Apr15.154147.10556@cm.cf.ac.uk> <1993Apr16.065919.103320@eratu.rz.uni-konstanz.de> Organization: Veda Systems, Iceland Lines: 25 zh@news.uni-konstanz.de (Z. Horvat) writes: >The told me that they gave my "old" board to someone who is now >successfully running OS2 on it. >This sounds strange to me, as i would have expected that one would >not even be able to run DOS software properly on such a board. The DOS and OS/2 probably *expect* the motherboard to be broken in this way (cache and DMA hardware subsystems unaware of each other), and therefore compensate for it in software. 386bsd 0.1 on the other hand expects the motherboard to have integrated cache and DMA, and is less forgiving in this respect. If someone points me to the relevant code, I'll gladly put some time into fixing this (I am assuming that locating the danger zone in the source would take me far longer than making it safe). I do not expect to be making any 100% fixes, because this will (hopefully) be completely overhauled in 0.2 anyway. I do however have a pressing incentive to get this gaping hole covered (there seems to be no easy way to tell whether the motherboard is broken without installing 386bsd and trying to use it for serious work). Also I would welcome some advice about how to program the 386/486 to mark certain areas as uncacheable. -- Adam D. (adam@veda.is)