Date: Wed, 17 Feb 1999 16:03:50 -0800 From: Kent Stewart <kstewart@3-cities.com> To: pmg@Quetico.tbaytel.net Cc: freebsd-questions@FreeBSD.ORG Subject: Re: BSD filesystems & MBR Message-ID: <36CB58E6.772843AC@3-cities.com> References: <36CADA56.67D2@mail.tbaytel.net>
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pmg wrote: > > i have a question about disk formatting and the DOS MBR. > > is there any reason at all to reserve a spot (1 block?), > using fdisk or whatever, at the beginning of a disk > that will be used solely for FreeBSD? > if the 'a' partition starts at absolute sector 0 > (sector 1 in DOS speak), > relative to the disk, not just the slice, > will FreeBSD ever interact with the MRB, or vicey-vous? > or, does FreeBSD always leave the 1st block of > a file partition (not a swap) untouched? > alternatively, will fdisk or any other similar DOS-like > utility mess up the freeBSD disk label or the 'a' partition? > > i like the idea of using fdisk just to keep a record on the disk > of the geometry, even if i'm only using a single slice for FreeBSD, > but i'm wondering if it would be more prudent to move that slice > on down a bit just to keep it out of harm's way. > moving it down a bit has no effect on the geometry of the slice on scsi > drives, since their geometry is virtual anyway. > but it seems to me that on ide drives you would have to make the move > 1 cylinder, or a integer number of cylinders. > otherwise, the geometry of the slice will be discombobulated with > respect to underlying geometry of the disk. > what about modern eide drives that remap their real geometry anyway??? > > fundamental question: will fdisk and FreeBSD play together nicely > on the 1st block of a disk??? My experience with BSD and the MBR depends on your HD. I have some Western Digital Caviar's that hang my system at boot if the DOS MBR isn't there. I joked that they didn't get SMART'er they got dumber. I didn't have any tools that would turn SMART off. Recovering from the BSD MBR involved low level formating (writing zeros) using WDDiag. You remove the disk from the Bios and then, you had to tell WDDiag which port the disk was on (0x1f0 or 0x170) and then select drive 0 or 1. I tried various combinations and after 4 or 5 tries and a 100% failure rate, I opted for the DOS MBR. Fortunately, the drives were relatively small ones at 3.1GB and only required 20-30 minutes each to LLF. -- Kent Stewart Richland, WA mailto:kstewart@3-cities.com http://www.3-cities.com/~kstewart/index.html To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-questions" in the body of the message
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