Date: Mon, 1 Sep 1997 19:20:45 -0700 From: Jonathan Mini <j_mini@efn.org> To: Mike Smith <mike@smith.net.au> Cc: emulation@FreeBSD.ORG Subject: Re: Fun with DOSCMD (was Re: modifying boot mgrs FROM FREEBSD)' Message-ID: <19970901192045.39217@micron.efn.org> In-Reply-To: <199709020156.LAA00629@word.smith.net.au>; from Mike Smith on Tue, Sep 02, 1997 at 11:26:18AM %2B0930 References: <19970901024217.20763@micron.efn.org> <199709020156.LAA00629@word.smith.net.au>
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Mike Smith stands accused of saying : > > > It certainly makes no sense to attempt to reenter the video BIOS, but > > > in at least the trivial sense there is nothing stopping me calling, > > > say, an ESCD function in one virtual x86 context while the video BIOS > > > is being called in another; remember that they are operating in > > > distinct virtual contexts, where the only risk of conflict is in the > > > I/O domain. > > > > Umm. I hope you are rembering about memory-address registers? :) > > That is indeed what "I/O domain" means; the only resource shared > between vm86 threads is hardware. > > > My problem is : "why can't I call the disk simulator's BIOS when I am using > > the video simulator's BIOS at the same time?" and there are too many reasons > > why not. (things like asking for a keypress and askingfor disk i/o > > simultaneously will crash Win95) > > I don't think I understand you here. You are saying that someone > else's BIOS implementation is nonreentrant, correct? That's more or > less to be expected... I'm sorry -- I was refering to simultaneous calls to _different_ BIOS's as opposed to simultaneous calls to the same BIOS, i.e. the BIOS on a SCSI card as opposed to the BIOS onboard the mb. also remember that many BIOS's store information within the BIOS/DOS "communication" aread, and the BIOS need to be able to access this. -- Jonathan Mini (j_mini@efn.org) Ingenious Productions Software Development P.O. Box 5693 Eugene, Or 97405
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