Date: Thu, 18 Feb 1999 20:00:10 -0800 From: Kent Stewart <kstewart@3-cities.com> To: Greg Lehey <grog@lemis.com> Cc: Riccardo Veraldi <riccardo@righi.ml.org>, freebsd-questions@FreeBSD.ORG Subject: Re: HOW to format ? Message-ID: <36CCE1CA.493CFB51@3-cities.com> References: <Pine.BSF.4.05.9501011021560.649-100000@righi.ml.org> <36CC3F61.91EB4912@3-cities.com> <19990219082520.N14890@lemis.com> <36CCCADE.E2A39877@3-cities.com> <19990219131001.B22647@lemis.com>
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Greg Lehey wrote: > > On Thursday, 18 February 1999 at 18:22:22 -0800, Kent Stewart wrote: > > Greg Lehey wrote: > >> Formatting involves a whole lot more than writing zeros to the disk. > >> It writes the sector headers as well, and the pattern that it writes > >> is designed to be relatively difficult to read, so that the > >> verification pass can catch flaky sectors. > > > > My bios'es (Award and Phoenix on 5 different computers) don't support IDE > > formating. I had a couple of ancient systems that did but nothing dated > > after 1996, which is my oldest bios. The "write zeros" is the menu option > > used to start a low level format in the WD utility program. In addition, > > WDDiag does a disk scan when it finishes, which can involve mapping > > replacement sectors into the sequence and giving you a full set. It is much > > more involved than anything provided via the bios. > > OK, I can't see your BIOS, and it's possible that they don't provide > the function, but writing zeros is not formatting. I agree, but it is the menu option and that is how Western Digital explains it to their casual customers. If you want someone to LLF a WD disk, that is what you have to tell them to do. > > >> You almost never need to reformat a disk. This is a Microsoftism. > >> FreeBSD reports disk I/O errors, so you should know when a format is > >> needed. > > > > This part isn't always true from my experience. If I write a FreeBSD MBR to > > any of my Western Digital Caviar Drives with SMART, the system will not boot > > past the first HD test after finishing counting memory. In order to recover > > the drive, I had remove it from the bios and then boot from the floppy. I > > could then use WDDiag to low level format the drive using the appropriate > > I/O port (0x1f0 or 0x170) and offset. > > Sure, low-level formatting will remove the MBR. You can also use it > for deleting files: it does quite a good job, but it's rather > non-specific. In this case, for example, you also removed your > FreeBSD partition. To repeat: you almost never need to reformat a > disk. In this case you seem to have geometry problems which you could > fix by writing a correct MBR and without losing the rest of the data > on the disk. > > > Next, you add the drive back into the bios and boot from the DOS > > floppy again. At this point you can "fdisk /mbr" and have a working > > drive that will not hang my system. > > Are you saying that Microsoft's FDISK won't write an MBR unless you > first low-level format it? That hasn't been my experience, but it > does tend to prove my claim that it's a Microsoftism. In any case, to > overwrite the MBR you can use dd and save your file systems. You > don't need to format, and formatting is detrimental. You can not boot with the modified MBR drive installed in the bios. You can't use dd to correct the problem unless the drive is installed - catch 22. It isn't geometry but it is probably an interaction between SMART not understanding the non-DOS MBR on the Caviar and responding to the early bios check. All of the new IDE's are coming with SMART built in. I have only tried to install FreeBSD on Western Digital Caviar's. I have joked that the drives haven't gotten SMART'er, they have gotten dumber. At any rate, if you modify the mbr, the system hangs. In order, to restore the DOS MBR with fdisk, you have to go through the sequence I listed above before you can include the drive in the bios. You could probably use dd at that point but a simple DOS boot with only the offending drive installed is very fast and it knows how to do the "fdisk /mbr" very quickly. The WD utility is something special for WD HD's and it does pure port I/O to correct the situation. They don't have a version for Linux or FreeBSD. I don't know why the system hangs; however, I tried all of the installation combinations on two different WD 3.1GB drives and it failed 100%. After doing 4 or 5 LLF's, I was convienced that I shouldn't use the modified MBR. We have a saying that "I was snake bit" and that still describes my sensitivity to touching the MBR. Kent > > Greg > -- > When replying to this message, please copy the original recipients. > For more information, see http://www.lemis.com/questions.html > See complete headers for address, home page and phone numbers > finger grog@lemis.com for PGP public key > > To Unsubscribe: send mail to majordomo@FreeBSD.org > with "unsubscribe freebsd-questions" in the body of the message -- Kent Stewart Richland, WA mailto:kstewart@3-cities.com http://www.3-cities.com/~kstewart/index.html Hunting Archibald Stewart, b 1802 in Ballymena, Antrim Co., NIR http://www.3-cities.com/~kstewart/genealogy/archibald_stewart.html To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-questions" in the body of the message
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