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Re: [Wlug] Partition table blues

by doug waud

Hi again Greg Gregory Avedissian wrote: > Thanks, Charles. I was afraid that hdb designation would be confusing. > That's just temporary, so I can do things to that drive from a working > linux intall on another disk. I've got three drives within reach of the > IDE cables, and I keep switching cables and jumpers to do all this. Now why did you not let us know that right from the start!? In particular, your second post had lines like > dd if=/dev/hda of=/boot/boot.MBR bs=512 count=1 > dd if=/dev/hda of=/boot/boot.446.MBR bs=446 count=1 > > I restored with: > > dd if=/boot/boot.MBR of=/dev/hda bs=512 count=1 all of which referred to /dev/hda! It is hard to tell without mind-reading exactly what you did. Do you see why you *must* tell us *exactly* what you did/are doing. There is no way we can guess that you moved the drive from /dev/hda to /dev/hdb (and god-knows-what-else!). In turn, if we are assuming the /dev/hda you reported is correct, we stand a good chance of telling you to do something which could be a disaster if it is mounted as /dev/hdb. Now I hope you can see why I kept harping on telling us *what* you did rather than what you *think* you did. > The disk in question is around 30GB, and originally, 6 GB were taken by > windows on hda1, 1GB by swap on hda2, 8GB for hda3, and 10GB for hda5, > leaving 3.7GB unallocated space in the extended partition. I did this by > making the win partition with the win98 fdisk, and then making the linux > partitions with the suse intall disk. It looks like the numbers aren't > adding up right. > >> >>> Disk /dev/hdb: 1123 cylinders, 255 heads, 63 sectors/track >> >> >> >> That equals 18040995 sectors of 512 bytes/each = 9,236,989,440 bytes Yes! You claim it is a 30 gig disk and, as Chuck points out, it is coming out about 9. Note that this is even before you get into the details of partitions. At this point I have not the slightest idea of where we are, especially since you have been swapping drives in god-knows-what order and fdisk /mbr on again an unknown (to us) drive. >> (snip,snip) >> The Win95 partition is just about the entire disk, leaving only 31.5 >> 1024-byte blocks left = 32,256 bytes. Where could any Linux >> partitions have fit? > > > On the other 24GB which appear not to be partitioned. See comments above, the summary for /dev/hdb *total* says there are not another 24 GB! > I'm a little > bothered by the math, though. You came up with 9GB, and I made that > partition 6GB. You *think* you did. It would appear the fact is that you really do not know what you did! >>> OK, one more idea. Can I use the partition tool to set the partitions >>> again without formatting them, and then be able to access them? >> >> If you are absolutely sure of the correct start/end of all the >> partitions on the disk, then yes, you should be able to re-set them in >> the partition table and regain access to the data without formatting >> them. This is much more likely to happen if there are no extended >> partitions (hdb5 or higher). Chuck, you are more optimistic than I! :-) I think that right now we are flying blind. Also, he now refers to a /dev/hd5 and and extended partition, so the cards would appear to be stacked even more solidly against him. > > No, I'm not sure, just assuming that if I use the same partition tool > with the same drive, it'll come up with the same numbers. Guess I need > to double-check the size of my win partition and make sure it hasn't > changed. In fact, I seem to recall noticing that hda1 ended well below > cyl 1023 when I set it up. At 8225280 bytes/cylinder, 6GB should end at > cyl 750, not 1125. The partition tool shows the end of hda1 at 1023, and > the end of hda2 at 1154. Uh-oh. Now, once again, that comes out of the blue (unless I lost something in all this long exchange). You just give the numbers in your edited version rather than tell us *exactly* what you did and then show us *exactly* what came out. > I better sleep on it before I do anything else. As I indicated earlier, prayer might be more effective! > Maybe parted didn't work because I gave it the wrong numbers? That "it' says a lot! Yes, wrong numbers is one of a zillion (and climbing) possibilities. doug

July 26, 2004

Re: [Wlug] Partition table blues

by Gregory Avedissian

Thanks, Charles. I was afraid that hdb designation would be confusing. That's just temporary, so I can do things to that drive from a working linux intall on another disk. I've got three drives within reach of the IDE cables, and I keep switching cables and jumpers to do all this. The disk in question is around 30GB, and originally, 6 GB were taken by windows on hda1, 1GB by swap on hda2, 8GB for hda3, and 10GB for hda5, leaving 3.7GB unallocated space in the extended partition. I did this by making the win partition with the win98 fdisk, and then making the linux partitions with the suse intall disk. It looks like the numbers aren't adding up right. > >>Disk /dev/hdb: 1123 cylinders, 255 heads, 63 sectors/track > > > That equals 18040995 sectors of 512 bytes/each = 9,236,989,440 bytes > total. > > >>Units = cylinders of 8225280 bytes, blocks of 1024 bytes, counting from 0 > > > Taking the blocks as 1024 bytes, thats 9020497.5 blocks. > > >> Device Boot Start End #cyls #blocks Id System >>/dev/hdb1 * 0+ 1122 1123- 9020466 c Win95 FAT32 (LBA) > > > The Win95 partition is just about the entire disk, leaving only 31.5 > 1024-byte blocks left = 32,256 bytes. Where could any Linux > partitions have fit? On the other 24GB which appear not to be partitioned. I'm a little bothered by the math, though. You came up with 9GB, and I made that partition 6GB. > > >>OK, one more idea. Can I use the partition tool to set the partitions >>again without formatting them, and then be able to access them? > > > If you are absolutely sure of the correct start/end of all the > partitions on the disk, then yes, you should be able to re-set them in > the partition table and regain access to the data without formatting > them. This is much more likely to happen if there are no extended > partitions (hdb5 or higher). > No, I'm not sure, just assuming that if I use the same partition tool with the same drive, it'll come up with the same numbers. Guess I need to double-check the size of my win partition and make sure it hasn't changed. In fact, I seem to recall noticing that hda1 ended well below cyl 1023 when I set it up. At 8225280 bytes/cylinder, 6GB should end at cyl 750, not 1125. The partition tool shows the end of hda1 at 1023, and the end of hda2 at 1154. Uh-oh. I better sleep on it before I do anything else. Maybe parted didn't work because I gave it the wrong numbers? Thanks, Greg

July 26, 2004

Re: [Wlug] Partition table blues

by Charles R. Anderson

On Sun, Jul 25, 2004 at 10:34:39PM -0400, Gregory Avedissian wrote: > That was linux fdisk I was talking about. It only shows the windows > partition. sfdisk -l shows four partitions - one windows, and three empty > ones, with no start or end cylinders. I'm not sure what that's about. There are always 4 primary partition entries in the partition table in first sector of the drive (MBR). The unused ones are filled with zeros. > Disk /dev/hdb: 1123 cylinders, 255 heads, 63 sectors/track That equals 18040995 sectors of 512 bytes/each = 9,236,989,440 bytes total. > Units = cylinders of 8225280 bytes, blocks of 1024 bytes, counting from 0 Taking the blocks as 1024 bytes, thats 9020497.5 blocks. > Device Boot Start End #cyls #blocks Id System > /dev/hdb1 * 0+ 1122 1123- 9020466 c Win95 FAT32 (LBA) The Win95 partition is just about the entire disk, leaving only 31.5 1024-byte blocks left = 32,256 bytes. Where could any Linux partitions have fit? > OK, one more idea. Can I use the partition tool to set the partitions > again without formatting them, and then be able to access them? If you are absolutely sure of the correct start/end of all the partitions on the disk, then yes, you should be able to re-set them in the partition table and regain access to the data without formatting them. This is much more likely to happen if there are no extended partitions (hdb5 or higher). What happened to make Windows take over the entire disk? Are you sure /dev/hdb is still /dev/hdb, and didn't change due to a disk failure or recabling of the IDE bus? Is Windows 98 installed to /dev/hdb1? It is highly unusual to have Windows boot from anything other than /dev/hdaN.

July 26, 2004

Re: [Wlug] Partition table blues

by Gregory Avedissian

Doug, That was linux fdisk I was talking about. It only shows the windows partition. sfdisk -l shows four partitions - one windows, and three empty ones, with no start or end cylinders. I'm not sure what that's about. Here's the output for fdisk and sfdisk when that drive is hooked up as slave: fdisk -l Device Boot Start End Blocks Id System /dev/hdb1 * 1 1123 9020466 c Win95 FAT32 (LBA) sfdisk -l Disk /dev/hdb: 1123 cylinders, 255 heads, 63 sectors/track Units = cylinders of 8225280 bytes, blocks of 1024 bytes, counting from 0 Device Boot Start End #cyls #blocks Id System /dev/hdb1 * 0+ 1122 1123- 9020466 c Win95 FAT32 (LBA) /dev/hdb2 0 - 0 0 0 Empty /dev/hdb3 0 - 0 0 0 Empty /dev/hdb4 0 - 0 0 0 Empty Here's what I tried. I went into yast2 partitioning tool, setup the drive the way I did the first time, wrote down the cylinder numbers, then hit ABORT, so it wouldn't write to the disk. Then ran "parted -i /dev/hdb", then used the cylinder numbers for the "rescue partitions near START and END" function. It scanned, returned no errors, and made no changes. I don't get it, and I'm out of ideas for now. OK, one more idea. Can I use the partition tool to set the partitions again without formatting them, and then be able to access them? Thanks for all your help, Greg doug waud wrote: > Hi again > > Gregory Avedissian wrote: > >> Hi Doug, >> >> I tried fdisk /mbr and it worked easily. As expected, I only have a >> windows partition (verified by fdisk). I suspect that I'm less than >> halfway there. > > > I'm glad you finally tried that! At least the easy part is taken care of > so you can now focus on a smaller problem. > > I admit to some guessing here, but I would suggest you try both the > Windows fdisk (just because I am a bit anal; I don't expect it to know > about the linux partitions) and the Linux fdisk. (You may have done this > but I can't tell since you say just "fdisk".) > >>> However, once that is working, you can boot into your linux system >>> (by one of the ways I mentioned in an earlier post, and run LILO >>> which is smart enough to leave the Windows part working and simply >>> add the stuff for other things you want to boot (as specified in >>> lilo.conf --- which I assume is OK if it was working earlier and you >>> have not edited it). >> >> >> No, there's no lilo.conf and never was one on that installation. > > > Oops! Sorry about that; I misread an earlier email. :-( > >> There is (was) a grub/menu.lst, which serves the same function, but as >> far as I understand it, the partition table needs to contain >> information about linux partitions for either of these to work. > > > I suspect that is true (can't recall off hand). If so, then remember to > pray when you run the Linux fdisk! :- > > And do run the linux fdisk, i.e. > fdisk /dev/hda > and then chose option p (as in *P*rint the partition table. If you get a > nice listing, then don't screw around with parted! > > >> I went ahead and booted the rescue system and tried a grub-install >> /dev/hda, and it returned a message saying that no /dev/root was found. >> >> Maybe I'll try parted again, now that I can find where hda1 ends. > > > But do try both Windows fdisk and Linux fdisk (with the P option) first! > > doug > > _______________________________________________ > Wlug mailing list > Wlug(a)mail.wlug.org > http://mail.wlug.org/mailman/listinfo/wlug >

July 26, 2004

Re: [Wlug] Partition table blues

by doug waud

Hi again Gregory Avedissian wrote: > Hi Doug, > > I tried fdisk /mbr and it worked easily. As expected, I only have a > windows partition (verified by fdisk). I suspect that I'm less than > halfway there. I'm glad you finally tried that! At least the easy part is taken care of so you can now focus on a smaller problem. I admit to some guessing here, but I would suggest you try both the Windows fdisk (just because I am a bit anal; I don't expect it to know about the linux partitions) and the Linux fdisk. (You may have done this but I can't tell since you say just "fdisk".) >> However, once that is working, you can boot into your linux system (by >> one of the ways I mentioned in an earlier post, and run LILO which is >> smart enough to leave the Windows part working and simply add the >> stuff for other things you want to boot (as specified in lilo.conf >> --- which I assume is OK if it was working earlier and you have not >> edited it). > > No, there's no lilo.conf and never was one on that installation. Oops! Sorry about that; I misread an earlier email. :-( > There > is (was) a grub/menu.lst, which serves the same function, but as far as > I understand it, the partition table needs to contain information about > linux partitions for either of these to work. I suspect that is true (can't recall off hand). If so, then remember to pray when you run the Linux fdisk! :- And do run the linux fdisk, i.e. fdisk /dev/hda and then chose option p (as in *P*rint the partition table. If you get a nice listing, then don't screw around with parted! > I went ahead and booted the rescue system and tried a grub-install > /dev/hda, and it returned a message saying that no /dev/root was found. > > Maybe I'll try parted again, now that I can find where hda1 ends. But do try both Windows fdisk and Linux fdisk (with the P option) first! doug

July 26, 2004

Re: [Wlug] Partition table blues

by Gregory Avedissian

Hi Doug, I tried fdisk /mbr and it worked easily. As expected, I only have a windows partition (verified by fdisk). I suspect that I'm less than halfway there. > >> This morning, I read that it shouldn't be used on disks that have more >> than four partitions. I have five partitions and some unclaimed space. >> I might try it later today. > > > I don't know where that came from. It came from ms. Maybe they're just playin' with our heads. > > However, once that is working, you can boot into your linux system (by > one of the ways I mentioned in an earlier post, and run LILO which is > smart enough to leave the Windows part working and simply add the stuff > for other things you want to boot (as specified in lilo.conf --- which > I assume is OK if it was working earlier and you have not edited it). No, there's no lilo.conf and never was one on that installation. There is (was) a grub/menu.lst, which serves the same function, but as far as I understand it, the partition table needs to contain information about linux partitions for either of these to work. I went ahead and booted the rescue system and tried a grub-install /dev/hda, and it returned a message saying that no /dev/root was found. Maybe I'll try parted again, now that I can find where hda1 ends. Thanks, Greg

July 26, 2004

Re: [Wlug] Partition table blues

by doug waud

Hi all (again!) J Schonberg wrote: > I know that the original question was based on a suse8.2 installation > but I'm guessing this is the Linux 2.6 kernel bug that has been > discussed at length in other places. Have you tried sfdisk? I don't follow your logic. Since Greg is using SuSE 8.2, he is a long way from a 2.6 kernel. So I don't see how you can diagnose his problem as a 2.6 not-ready-for-prime-time bug. doug

July 25, 2004

Re: [Wlug] Partition table blues

by Gregory Avedissian

Hi Doug, I haven't tried fdisk /mbr because I don't really fully understand what it does and have never seen a good explanation of how it will affect linux partitions. This morning, I read that it shouldn't be used on disks that have more than four partitions. I have five partitions and some unclaimed space. I might try it later today. Beside that, anything of value is on the linux side of the disk. (That's not a microsoft slur, it's just where I have my files.) So, while I would like to be able to get the whole thing back to its original working order as a learning exercise, I'm more motivated to get to the linux partitions. Thanks again, Greg doug waud wrote: > Hi again > > This time, let's try focussing on one thing to try. > > I don't see that you have ever tried the standard way to restore the MBR > for Windows --- boot a Windows floppy with fdisk on it and type > fdisk /mbr > and, if you still cannot boot windows, add a > sys c: > > It is not clear from here why you did not try this. > > doug > > > Gregory Avedissian wrote: > >> doug waud wrote: >> >>> Hi again Greg >>> >>> Gregory Avedissian wrote: >>> >>>> There were three backups of the mbr. One made under dos with >>>> debug.exe, and the others made with linux as, >>>> >>>> dd if=/dev/hda of=/boot/boot.MBR bs=512 count=1 >>>> dd if=/dev/hda of=/boot/boot.446.MBR bs=446 count=1 >>>> >>>> I restored with: >>>> >>>> dd if=/boot/boot.MBR of=/dev/hda bs=512 count=1 >>>> I think maybe I picked the wrong one. >> >> >> >> > I admit I would have used the second, safer (since it does not >> touch the >> > partition table), but I don't see why the 512 bs variant would not >> have >> > worked unless you had changed the partition table since making that >> > boot.MBR file. >> >> No, I didn't change the partition table. I made these backups within >> days of installing, so that I would have copies of a new, working mbr. >> >>> >>> It is hard to tell what went wrong until you tell us what you were >>> doing just before the system no longer would boot. (Those two lines >>> creating the boot.xyz files would only read from the first 512 or 446 >>> bytes not do any writing there so they cannot be the cause of your >>> troubles.) >>> >>> >>> Why don't you boot from a bootable floppy? Alternatively, start the >>> SuSE recovery mechanism which includes "boot an installed system" as >>> an option. If all that is screwed up it the MBR, you could then >>> simply run LILO to refresh it. >>> >> >> I had a new win98 installation working ok, then I installed suse8.2 >> and set it up so that it would boot with GRUB from floppy. I don't recall >> if I ever tried to boot from the harddrive to get into windows after I >> installed suse, but I know I could get there from the floppy. >> >> When I did try to boot off the hard drive two days ago, it hung with >> the message, "Disk boot failure. Insert system disk." >> >> I could still boot to win or linux from the grub floppy at this point. >> I tried restoring the mbr in dos with debug.exe, and that didn't help. >> I could still boot to linux with the floppy, and I can't remember if I >> could still boot to windows. Then I tried restoring with >> dd if=/boot/boot.MBR of=/dev/hda bs=512 count=1 >> >> After that, I couldn't boot from the grub floppy anymore. Trying to >> boot the installed system from the rescue disk also failed. I then >> booted to the rescue system. Output of sfdisk -l looked like this: >> >> Disk /dev/hda: 3737 cylinders, 255 heads, 63 sectors/track >> /dev/hda: unrecognized partition >> No partitions found >> >> Repeating the restore procedure with debug.exe didn't help, either. >> >> >> Thanks, >> Greg >> > > _______________________________________________ > Wlug mailing list > Wlug(a)mail.wlug.org > http://mail.wlug.org/mailman/listinfo/wlug >

July 25, 2004

Re: [Wlug] Partition table blues

by J Schonberg

I know that the original question was based on a suse8.2 installation but I'm guessing this is the Linux 2.6 kernel bug that has been discussed at length in other places. Have you tried sfdisk? Details and a solution here : http://www.redhat.com/archives/fedora-devel-list/2004-May/msg00908.html Cheers. Jason. --- doug waud <douglas.waud(a)umassmed.edu> wrote: > Hi again > > This time, let's try focussing on one thing to try. > > I don't see that you have ever tried the standard way to restore > the MBR > for Windows --- boot a Windows floppy with fdisk on it and type > fdisk /mbr > and, if you still cannot boot windows, add a > sys c: > > It is not clear from here why you did not try this. > > doug > > > Gregory Avedissian wrote: > > doug waud wrote: > > > >> Hi again Greg > >> > >> Gregory Avedissian wrote: > >> > >>> There were three backups of the mbr. One made under dos with > >>> debug.exe, and the others made with linux as, > >>> > >>> dd if=/dev/hda of=/boot/boot.MBR bs=512 count=1 > >>> dd if=/dev/hda of=/boot/boot.446.MBR bs=446 count=1 > >>> > >>> I restored with: > >>> > >>> dd if=/boot/boot.MBR of=/dev/hda bs=512 count=1 > >>> I think maybe I picked the wrong one. > > > > > > > I admit I would have used the second, safer (since it does not > touch the > > > partition table), but I don't see why the 512 bs variant would > not have > > > worked unless you had changed the partition table since making > that > > > boot.MBR file. > > > > No, I didn't change the partition table. I made these backups > within > > days of installing, so that I would have copies of a new, working > mbr. > > > >> > >> It is hard to tell what went wrong until you tell us what you > were > >> doing just before the system no longer would boot. (Those two > lines > >> creating the boot.xyz files would only read from the first 512 > or 446 > >> bytes not do any writing there so they cannot be the cause of > your > >> troubles.) > >> > >> > >> Why don't you boot from a bootable floppy? Alternatively, start > the > >> SuSE recovery mechanism which includes "boot an installed > system" as > >> an option. If all that is screwed up it the MBR, you could then > simply > >> run LILO to refresh it. > >> > > > > I had a new win98 installation working ok, then I installed > suse8.2 > > and set it up so that it would boot with GRUB from floppy. I > don't recall > > if I ever tried to boot from the harddrive to get into windows > after I > > installed suse, but I know I could get there from the floppy. > > > > When I did try to boot off the hard drive two days ago, it hung > with the > > message, "Disk boot failure. Insert system disk." > > > > I could still boot to win or linux from the grub floppy at this > point. I > > tried restoring the mbr in dos with debug.exe, and that didn't > help. I > > could still boot to linux with the floppy, and I can't remember > if I > > could still boot to windows. Then I tried restoring with > > dd if=/boot/boot.MBR of=/dev/hda bs=512 count=1 > > > > After that, I couldn't boot from the grub floppy anymore. Trying > to boot > > the installed system from the rescue disk also failed. I then > booted to > > the rescue system. Output of sfdisk -l looked like this: > > > > Disk /dev/hda: 3737 cylinders, 255 heads, 63 sectors/track > > /dev/hda: unrecognized partition > > No partitions found > > > > Repeating the restore procedure with debug.exe didn't help, > either. > > > > > > Thanks, > > Greg > > > > _______________________________________________ > Wlug mailing list > Wlug(a)mail.wlug.org > http://mail.wlug.org/mailman/listinfo/wlug > __________________________________ Do you Yahoo!? Yahoo! Mail - 50x more storage than other providers! http://promotions.yahoo.com/new_mail

July 25, 2004

Re: [Wlug] Partition table blues

by doug waud

Hi again This time, let's try focussing on one thing to try. I don't see that you have ever tried the standard way to restore the MBR for Windows --- boot a Windows floppy with fdisk on it and type fdisk /mbr and, if you still cannot boot windows, add a sys c: It is not clear from here why you did not try this. doug Gregory Avedissian wrote: > doug waud wrote: > >> Hi again Greg >> >> Gregory Avedissian wrote: >> >>> There were three backups of the mbr. One made under dos with >>> debug.exe, and the others made with linux as, >>> >>> dd if=/dev/hda of=/boot/boot.MBR bs=512 count=1 >>> dd if=/dev/hda of=/boot/boot.446.MBR bs=446 count=1 >>> >>> I restored with: >>> >>> dd if=/boot/boot.MBR of=/dev/hda bs=512 count=1 >>> I think maybe I picked the wrong one. > > > > I admit I would have used the second, safer (since it does not touch the > > partition table), but I don't see why the 512 bs variant would not have > > worked unless you had changed the partition table since making that > > boot.MBR file. > > No, I didn't change the partition table. I made these backups within > days of installing, so that I would have copies of a new, working mbr. > >> >> It is hard to tell what went wrong until you tell us what you were >> doing just before the system no longer would boot. (Those two lines >> creating the boot.xyz files would only read from the first 512 or 446 >> bytes not do any writing there so they cannot be the cause of your >> troubles.) >> >> >> Why don't you boot from a bootable floppy? Alternatively, start the >> SuSE recovery mechanism which includes "boot an installed system" as >> an option. If all that is screwed up it the MBR, you could then simply >> run LILO to refresh it. >> > > I had a new win98 installation working ok, then I installed suse8.2 > and set it up so that it would boot with GRUB from floppy. I don't recall > if I ever tried to boot from the harddrive to get into windows after I > installed suse, but I know I could get there from the floppy. > > When I did try to boot off the hard drive two days ago, it hung with the > message, "Disk boot failure. Insert system disk." > > I could still boot to win or linux from the grub floppy at this point. I > tried restoring the mbr in dos with debug.exe, and that didn't help. I > could still boot to linux with the floppy, and I can't remember if I > could still boot to windows. Then I tried restoring with > dd if=/boot/boot.MBR of=/dev/hda bs=512 count=1 > > After that, I couldn't boot from the grub floppy anymore. Trying to boot > the installed system from the rescue disk also failed. I then booted to > the rescue system. Output of sfdisk -l looked like this: > > Disk /dev/hda: 3737 cylinders, 255 heads, 63 sectors/track > /dev/hda: unrecognized partition > No partitions found > > Repeating the restore procedure with debug.exe didn't help, either. > > > Thanks, > Greg >

July 25, 2004