Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Path: utzoo!mnetor!uunet!husc6!rutgers!gatech!udel!mmdf From: A-PIRARD%BLIULG11.BITNET@wiscvm.wisc.edu (Andre PIRARD) Newsgroups: comp.os.minix Subject: Re: booting minix from dos Message-ID: <585@louie.udel.EDU> Date: Tue, 13-Oct-87 14:23:13 EDT Article-I.D.: louie.585 Posted: Tue Oct 13 14:23:13 1987 Date-Received: Thu, 15-Oct-87 02:11:07 EDT Sender: mmdf@udel.EDU Lines: 55 On this subject, here are two messages I posted to the INFO-IBMPC list. Due to the tricky problem of resetting the hardware correctly before booting, I feel this is hard to achieve from within any running system. Even more to come back to it. Hence my suggestion for a boot disk used to choose another. Of course, my suggestion to put it on a diskette depends heavily on how often one switches systems. My "special program" can of course be used in one hard disk partition of its own. Because Minix people probably often do, there must be interest on this list. I am not watching the list closely, more for a friend. So, if anyone undertakes anything that way, I'd be glad to receive a personal notice. Thanks. Date: Wed, 19 Aug 87 13:37:44 ULG From: Andre PIRARD Subject: Booting Another Partition from Within DOS When MSDOS has booted from the active partition, is there a way (program) to boot an inactive partition without FDISK reassignment then reset. It seems tricky to perform the necessary resets (e. g. interrupt vectors) and load the boot record without getting into very machine-dependent code. But I might have missed something... Thanks. Date: Thu, 03 Sep 87 11:18:47 ULG From: Andre PIRARD Subject: Booting Another Partition from Within DOS >When MSDOS has booted from the active partition, is there a way (program) >to boot an inactive partition without FDISK reassignment then reset. >It seems tricky to perform the necessary resets (e. g. interrupt vectors) >and load the boot record without getting into very machine-dependent code. >But I might have missed something... Thanks. Well, I did. In fact, there is no need to boot DOS. If performing the resets is difficult, let's simply go through the BIOS reset itself! The trick is to format a "special" diskette that contains a dummy IBMBIO.COM (or whatever name) that, when loaded, determines the available hard disks, reads their partition records and checks their validity (55AA tag). For each valid partition record, the partition table is examined for valid entries (both active or inactive) and the boot record they point to is again examined for the validity tag 55AA. This gives a list of bootable partitions that can be displayed on the screen with a prompt for the user to choose one (no national keyboard key used, just arrows and return). When done, the corresponding boot record is loaded at 0:7C00 and given control. That's all there is to it. When there is need to boot a partition other than the active one, the spe- cial diskette is inserted in drive A and the machine is reset with instant access to whatever system available Unix, CP/M or several DOS versions. But I have no time to program this. So I suggest the idea for an addition of a very special and funny program to the IBMPC library.