Date: Sat, 10 Feb 1996 13:41:33 -0700 (MST) From: Terry Lambert <terry@lambert.org> To: lague@hargray.com (Lague) Cc: questions@freebsd.org Subject: Re: Installation With Drive Overlay Message-ID: <199602102041.NAA16578@phaeton.artisoft.com> In-Reply-To: <311CBB9C.4EA2@hargray.com> from "Lague" at Feb 10, 96 10:37:00 am
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> I have something called "Drive Overlay" installed on my HD. It lets me > access my entire Hard Drive under MS-DOS. I am interested in installing > FreeBSD with BootEasy but am cautious. I believe, if I install > BootEasy, it will modify the boot record, correct? And If it does, will > I loose access to my DOS partition? Is there some workaround for this? > Maybe I could boot from the Dynamic Drive Overlay Partition and then it > would boot DOS? I believe this is a product like OnTrack DiskManager 6.x and 7.x which replaces the boot code with something like 64 sectors of boot loader for an INT 13 redirecting TSR and then makes the TSR do the geometry translation for you. OnTrack puts itself there with a fake partition entry that indicates that it's there and points to the real partition entry. Each disk access with the TSR loaded adds 64 to the absolute sector offest and accesses there instead. At the 64th sector, the normal DOS MBR is installed. The TSR loads it after it is loaded, and executes it. So the DOS MBR starts booting normally and *thinks* it's at the front of the disk. When BSD is installed, it knows to look for the OnTrack disk manager, but it doesn't necessarily know to look for the "Drive Overlay" code. So it is dangereous to install the BSD boot manager on this drive. What I recommend (even for OnTrack) is that you install normally, and then boot the DOS partition on the disk and install OS-BS from the DOS prompt -- this will make sure it is loaded AFTER the INT 13 TSR for geometry translation is loaded, so the MBR you replace will be the DOS MBR, not the "Disk Overlay" or "OnTrack" TSR-loading MBR. Don't install the OS-BS from the BSD install, since the OS-BS will be installed without the TSR loaded, and may not recognize it for what it is and install over the DOS MBR instead. 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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