Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!swrinde!zaphod.mps.ohio-state.edu!usc!snorkelwacker!bloom-beacon!eru!hagbard!sunic!mcsun!hp4nl!star.cs.vu.nl!sreiz From: sreiz@cs.vu.nl (Reiz Steven) Newsgroups: comp.sys.amiga Subject: Re: MINIX on the Amiga... Message-ID: <7726@star.cs.vu.nl> Date: 25 Sep 90 10:54:14 GMT References: <1990Sep24.114627.14857@watserv1.waterloo.edu> <1990Sep24.103505@wjg.enet.dec.com> Sender: news@cs.vu.nl Lines: 38 guineau@wjg.enet.dec.com (W. John Guineau) writes: >I've been talking with Andy Tanenbaum about Minix. >He says he doubts that it will run on a 68030 based machine >(ie A3000, A2500/30). Minix does not set up the MMU. >I figure if the power up state if the MMU is "safe mode" it should >be irrelevent. Doesn't the Amiga ROM (1.3) set up things like caches/MMU >registers before booting? >Has anyone gotten Minix running on one of these machines? Not having tried this myself I can only guess at the exact nature of the problems encountered when running Amiga Minix 1.5 on 680x0s where x>1: - The highest 8 bits of some addresses are used for a 'dirty trick' by the minix kernel. This means that you must be able to instruct your 68020/ 68030 board to use 24 bit addressing, like the 68000 and 68010. - Minix can't access memory outside the 16 MB range. This is caused by the way addresses are encoded in the memory manager. I don't know if any 68020/68030 boards really have memory outside the 16 MB range, but this doesn't seem a very serious problem to me anyhow. - Last but certainly not least: minix doesn't take take the different layout /size into account of the exception frames saved by the 68010, 68020 and 68030 for certain exceptions. This will crash your machine as soon as an address error (or other exceptions?) is encountered. Amiga Minix is started from s:startup-sequence, so you can fiddle with the MMU and cache parameters as much as you like before running minix, by calling the utility program that came with your accelerator board from the startup- sequence before minix is started. I think that the same parameters could be used that are used for the normal AmigaOS. > >-- >W. John Guineau guineau@wjg.enet.dec.com >Digital Equipment Corporation >Marlboro MA. 01752 Steven Reiz