Date: Tue, 21 May 1996 11:03:09 -0700 (MST) From: Terry Lambert <terry@lambert.org> To: smbrown@cisco.com (Stephen M. Brown) Cc: questions@freebsd.org Subject: Re: Install boo-boo Message-ID: <199605211803.LAA01534@phaeton.artisoft.com> In-Reply-To: <2.2.32.19960521034453.00a3b888@diablo.cisco.com> from "Stephen M. Brown" at May 20, 96 08:44:53 pm
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> Went through the initial boot from boot.flp, creating a freebsd partion on > wd1 leaving wd0 untouched but choosing the bootmanager option. Didn't > actually have the distribution but went through the process anyway, perhaps > my first mistake? Choosing the boot manager option when installing on a second drive is a bad thing. The boot manager is written to the first drive. You must now recover. There are two potential types of recovery: 1) wd0 did *not* have OnTrack or another MBR based LBA using INT 13 geometry translator Identification: You will see one or more valid partitions when you boot from floppy and run fdisk. If this is the case, then the standard MBR was overwritten by the boot selector from BSD. Then, when it went to mark a partition active, it couldn't find one, and now you have no active partition. Fix: boot a DOS floppy and run fdisk. Mark one of the partitions active. Problem solved. 2) wd0 *did* have OnTrack or another MBR based LBA using INT 13 geometry translator Identification: You will see one partition when you boot from floppy and run fdisk. You will not recognize the partition ID. Because the BIOS geometry is unknown to BSD because there is no way to call INT 13 AH=0x08 AL=0x80 from the kernel (needs a VM86() call gate), the replacement boot selector MBR overwrote the first part of the OnTRack or other MBR based LBA using INT 13 geometry translator. You will need to reinstall it from the disks which came with your system. There should be an option to allow you to do this without overwriting the partition table data. Once this is done, you need to boot DOS from the repaired drive do that the translator is installed during the boot process (remember that it was not installed when BSD wrote the MBR because BSD does not use BIOS to write the disk). Once you have booted to a DOS prompt (or, for Windows95, "Start, Shutdown..., Restart the computer in MS-DOS mode, Yes"), then you can install OS-BS.EXE from the DOS command line. This will put it over top of the real DOS MBR, which is at a translated offset instead of being at te start of the drive. > Now when the machine starts I get: NO ROM BASIC, SYSTEM HALTED and hangs. If the ROM POST initialization portion of the boot can't find a bootable device (by finding a valid boot record with an active partition), it will attempt to jump to the ROM BASIC location. Since most machines do not have the ROM BASIC because of licensing for BIOS clones, it has been replaces with a little code hunk to print out that message. You'd get the same message if you unplugged all the hard drives in almost any PC (almost, because some of them would start BASIC 8-)). > How do I make the boot disk (C:) available again? Tried doing fdisk /mbr to > recreate the MBR on the boot disk but no go. Please help. Bad plan, but you haven't damaged anything irreversably yet. Terry Lambert terry@lambert.org --- Any opinions in this posting are my own and not those of my present or previous employers.
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