Date: Thu, 8 Jun 1995 15:01:33 -0400 From: Temptation <temp@temptation.interlog.com> To: Terry Lambert <terry@cs.weber.edu> Cc: hlew@genome.Stanford.EDU, freebsd-hackers@freebsd.org Subject: Re: problem Message-ID: <Pine.3.89.9506081449.A3196-0100000@temptation.interlog.com> In-Reply-To: <9506081839.AA05420@cs.weber.edu>
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I know about DM (used for 5-40meg MFM/RLL drives many years ago) But as far as I know it was never on this drive, if it was, it's long gone, since i've Low-level formatted the drive a couple times. It's been a Novell server, NT server, NT workstation, Warp and Linux, and I usually low-level and run a Lowlevel-Scan before I install new OS's on them, to make sure the drive is clean, it's SCSI, so it doesn't hurt any to check them, unlike most IDE drives. I just fdisk and reformatted, don't have time to play with that stuff. On Thu, 8 Jun 1995, Terry Lambert wrote: > [ ... regarding "OnTrack Disk Manager" ... ] > > > No. it didn't require it. Nor did I use DM. a friend send me disk doctor. > > that data was there, but it Norton failed to retrieve it correctly. so > > it's history. > > You should run pfdisk.exe from a DOS disk and report the partition > information that exists on the drive. > > Many manufacturers use DM on your behalf and don't tell you about > it. > > I suspect you will find a single partition (and would like to know what > type it says it is), which is the magic indicator that you had an > OnTrack Disk Manager partition on the drive. > > The DM loads code in it's MBR to redirect INT 13/INT 21 by subtracting > 64 sectors (to account for itself) and then translating subsequent BIOS > calls relative to the area immediately after their MBR. > > Then immediately following that is the DOS MBR, which thinks it's at > 0, containing your partition table written using the DM translated > geometry. > > If this is the case, then all of your data is still there, and you need > another copy of the base 64 sectors, and everything will magically work > again. > > The problem is that when you boot off of floppy to install BSD, the DM > code is (of course) not loaded, and you don't see the translated geometry > or the 64 sector offset. > > What this would probably mean to you is that the BSD information is > offset 64 sectors into the DOS partitions end (usually not a problem > unless your drive was full under DOS, but something that should be > fixed anyway). > > For anything above and beyond an explanation (like a dump of the first > 64 sectors to replace those blown away, a utility to suck them off > another machine or write them to yours from a DOS booted floppy, etc.) > you will need to contact someone else who happens to have the stuff on > hand (I don't). > > A fix for BSD may be partially there already (I seem to remember that it > is from the list discussions), and probably has to do with the slicer > not offseting where it writes the partition table when the DM is > detected as present (or it simply not being detected). > > Note that DM is not the only utility that does this kind of crap, but > it is probably the best and most frequently (80-90%) used. > > > Terry Lambert > terry@cs.weber.edu > --- > Any opinions in this posting are my own and not those of my present > or previous employers. >
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