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Path: sserve!newshost.anu.edu.au!munnari.oz.au!news.Hawaii.Edu!ames!agate!agate.berkeley.edu!cgd From: cgd@erewhon.CS.Berkeley.EDU (Chris G. Demetriou) Newsgroups: comp.os.386bsd.bugs Subject: Re: my bug list Date: 30 Mar 93 02:13:41 Organization: Kernel Hackers 'r' Us Lines: 41 Message-ID: <CGD.93Mar30021341@erewhon.CS.Berkeley.EDU> References: <DERAADT.93Mar11154207@newt.fsa.ca> <1993Mar15.223046.10278@fcom.cc.utah.edu> <DERAADT.93Mar25200858@newt.fsa.ca> <1993Mar30.003656.2601@fcom.cc.utah.edu> NNTP-Posting-Host: erewhon.cs.berkeley.edu In-reply-to: terry@cs.weber.edu's message of Tue, 30 Mar 93 00:36:56 GMT just a couple of questions... In article <1993Mar30.003656.2601@fcom.cc.utah.edu> terry@cs.weber.edu (A Wizard of Earth C) writes: >You can't do a device/slot reset on an ISA bus. In order to cause a real >reset, you have to drop out of protected mode and hit the keyboard soft >reset code. This is not necessarily possible on all ISA machines due to >the way one has to drop out of protected mode generally causes a reset -- >and the BIOS is relied upon (incorrectly, for your machine) to issue a >bus reset as part of this. i don't understand this. _what_ about dropping out of protected mode causes a reset? (that's what your statement says, unless i misread it...) i've yet to understand why 386bsd doesn't use the standard keyboard-controller method of resetting the CPU. things like windows (obviously) can drop out of protected mode, without causing a reset, and i think that it *IS* valid to be able to expect 386bsd to be able to do the same. should be possible, at worst, by making the physical and virtual mappings of some part of the kernel match, being in that part, dropping out of protected mode, and then immediately using the keyboard controller reset method. this double mapping could take place right before reboot, or could even be done (as a hack) for *everything* -- a process's zero-page shouldn't be accessible to it anyway, and this would be a reasonable thing to put it in, if necessary... regardless of other points (i think that device shutdown routines are a good idea), the keyboard controller method is IMO (i make no claims of humility 8-) the correct way to reboot a PC, and causing the CPU to fault itself it death isn't... chris -- Chris G. Demetriou cgd@cs.berkeley.edu In case you didn't know: There are blondes and bogons in the VM system!