Re: [lfs-support] help, i hosed my windows partition
Hi everybody, Thanks for all the advice, so far. @Pierre: I'll give that a go, if all else fails. Somehow, removing the linux partition seems a bit scary, especially after my recent experience :) @akh: I'm afraid the disk cloning is not an option. My computer is a laptop, and it's the only one i got, atm, so I can't really attach the disk to another computer. Also, it's 500GB and i don't have another disk that size. @Aleksander: Hm, that doesn't sound too hopeful. To be honest, i don't need Windows, desperately, and I'm worried i'll screw up my linux partition, as well. I think I should probably read up a bit more on partitions and take it from there. Who knows, maybe it's even time to start from scratch... Thanks again, Tilman -- http://linuxfromscratch.org/mailman/listinfo/lfs-support FAQ: http://www.linuxfromscratch.org/lfs/faq.html Unsubscribe: See the above information page
Re: [lfs-support] help, i hosed my windows partition
Le 10/03/2013 10:33, tilmanbregler a écrit : Hi, so this is a bit emberassing, and I appreciate if you say this is nothing to do with you. I have this dual boot Ubuntu 12.04/Windows 7 setup. And to make room for th LFS partitions i decided to shrink the Windows 7 partition. [...] This is how my partition table looks, atm: sudo fdisk -l Disk /dev/sda: 750.2 GB, 750156374016 bytes 255 heads, 63 sectors/track, 91201 cylinders, total 1465149168 sectors Units = sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 4096 bytes I/O size (minimum/optimal): 4096 bytes / 4096 bytes Disk identifier: 0x05b005af Device Boot Start End Blocks Id System /dev/sda1 * 2048 206847 102400 7 HPFS/NTFS/exFAT /dev/sda3 206848 1465147391 732470272 5 Extended /dev/sda5 1024004096 1449783295 212889600 83 Linux /dev/sda6 1449785344 1465147391 7681024 82 Linux swap / Solaris Well, so which is your Ubuntu partition: /dev/sda5? It seems that there is a NTFS partition at /dev/sda1. What is it? I thought Windows needed only one partition, but maybe it is not true. Anyway, you could try two things: 1) Shrink the first partition by one sector (this involves shrinking first the filesystem), then remove the extended partition and recreate it starting at 206847 (this involves removing first /dev/sda5-6 and recreating them afterwards, at the same sectors of course, see 2) below for something slightly more detailed). Then recreate the Windows partition starting at 206848. 2) Remove first the extended partition /dev/sda3. This involves removing /dev/sda5 and 6, too, so you might loose your linux systems if something goes wrong. Of course, keep a track of the sectors of those partitions... -Create a primary partition (/dev/sda2) for the NTFS system starting at 206848 and with a size enough to contain your Windows system. -Recreate the extended partition starting just after /dev/sda2 and extending to the end of the disk. -Recreate logical partitions /dev/sda5 and 6 with the same sectors as before. -Cross fingers and write the table to disk (well, instead of crossing fingers, think long before you do, print the partition table and double check everything. As long as you do not type 'w', you cannot screw things more than they are...) Remember, all of this may fail for just one typo! Regards and good luck Pierre -- http://linuxfromscratch.org/mailman/listinfo/lfs-support FAQ: http://www.linuxfromscratch.org/lfs/faq.html Unsubscribe: See the above information page
Re: [lfs-support] help, i hosed my windows partition
Date: Sun, 10 Mar 2013 09:33:39 + From: tilmanbregler tilmanbreg...@gmail.com To: lfs-support@linuxfromscratch.org Subject: [lfs-support] help, i hosed my windows partition . . so this is a bit emberassing, and I appreciate if you say this is nothing to do with you. I have this dual boot Ubuntu 12.04/Windows 7 setup. And to make room for th LFS partitions i decided to shrink the Windows 7 partition. . . 206848. Any ideas how i can do that, or get back my windows partition, otherwise? Thanks in advance, Tilman The following is just about the first step - making a backup - and not about the subsequent recovery steps. In situations like this, it's a good idea to, as a zeroeth step: stop, do nothing to/with/for/on the disk for the time being, and think things through; don't take 'lunges' at it, or you run a quickly-escalating risk of being drawn (further) into the quicksand. Ideally, and before any further other operations on the disk, get a clone of it and verify that the clone is an accurate copy: that way, you have a backup/snapshot of your present state, that you can fall back on if necessary (at which stage you'd make a clone of the clone before proceeding, and so on). For making the clone, you will ideally need a spare additional disk that is empty and/or that you are OK to overwrite, and whose capacity is larger than the Ubuntu/'Win' disk. Ideally, take the present Ubuntu/'Win' disk and the 'spare additional disk', attach each as a dumb disk to another machine, and use dd to make the clone: but be very careful and clear about source and target disks, and dd usage - especially those common usages that will **WIPE** out your target disk - , and so on through the usual list of caveats, including that you want the 'another machine' to treat the Ubuntu/'Win' disk as a dumb disk, and not try to do anything fancy or 'automated' to the disk. If that's really not possible then can you attach the 'spare additional disk' to the original machine, boot into Ubuntu from the Ubuntu/'Win' disk, and use dd from there. Again, the same list of warnings c apply here as above. NB that this is a less-ideal situation than the one above, as here the Ubuntu/'Win' is not playing an 'inert'/'passive' role, because here you're booting from it. Once you have done the clone, test it (the clone) by trying to boot Ubuntu from it: ideally connect it to the original machine in place of the original Ubuntu/'Win' disk (temporarily, for the purposes of the test), connected in exactly the same way (same ports, etc). If/when you get to the login prompt, just login and do a graceful shutdown of the machine. You might also want to verify similarly that it will boot in another machine - or at least can be mounted and find/cat/ls works ok in another machine. But don't do anything beyond that - you don't want to be changing the clone (other than perhaps the login and command-history being recorded). If you don't have a 'spare additional disk' at all, then perhaps if possible consider obtaining one: it should be larger than the Ubuntu/'Win' disk, else you'd have to juggle a lot, with the risk of confusion and foot-shooting/branch-sawing. If you do have a 'spare additional disk' but can't afford to wipe it, then be aware that dd can write its output to an ordinary file. You'd still need to have enough spare space to write the clone-image file: else you're back to the stage of obtaining a suitable disk that has got enough space for making the clone. But you really must be careful, in this scenario, to not wipe the disk: you're, in this scenario, writing dd's output to an ordinary file in the filesystem of the 'spare additional disk'. And you've got some juggling and extra steps to do in verifying - or later using - the clone. Best, overall, to have a 'spare additional disk' that you can wipe and that is larger than the original Ubuntu/'Win' disk. Proceed with caution and deliberation. Keep a clear picture of what disks are where, what is on them at each stage, etc. Keep a clear picture of what you're doing: else back off for a bit until you do; again, don't take lunges at situations like this. hth, akh -- -- http://linuxfromscratch.org/mailman/listinfo/lfs-support FAQ: http://www.linuxfromscratch.org/lfs/faq.html Unsubscribe: See the above information page
Re: [lfs-support] help, i hosed my windows partition
On Sun, 10 Mar 2013 09:33:39 + tilmanbregler tilmanbreg...@gmail.com wrote: [snip] sudo fdisk -l Disk /dev/sda: 750.2 GB, 750156374016 bytes 255 heads, 63 sectors/track, 91201 cylinders, total 1465149168 sectors Units = sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 4096 bytes I/O size (minimum/optimal): 4096 bytes / 4096 bytes Disk identifier: 0x05b005af Device Boot Start End Blocks Id System /dev/sda1 * 2048 206847 102400 7 HPFS/NTFS/exFAT /dev/sda3 206848 1465147391 732470272 5 Extended /dev/sda5 1024004096 1449783295 212889600 83 Linux /dev/sda6 1449785344 1465147391 7681024 82 Linux swap / Solaris Ideally, i'd like to create the ntfs partition starting at sector 206848. Any ideas how i can do that, or get back my windows partition, otherwise? Thanks in advance, Tilman In short, what you wish to do is impossible, as such. The standard issue PC partition table has only four slots for partitions, called physical partitions. In the case more partitions are needed, the last partition gets subpartitioned. The subpartition table is kept at the start of the fourth partition. These subpartitions are called virtual partitions. So you are unable to make the NTFS partition start at 206848 presumably because that is the first sector of where the virtual partition table is being kept. If you did at one point write a 5-partition table to the disk, with the NTFS partition starting beyond sector 206848, with the content between the end of /dev/sda1 and the start of NTFS partition being unaccounted for, I am afraid that the start of your NTFS partition (and, by extension, NTFS filesystem) has been nuked. If, on the other hand, you did not write a 5-partition layout to the disk, it is still possible for the resizing of the NTFS filesystem to have hosed your Windows. This possibility has to do with bootloaders and the way they find later stages. Because the Master Boot Record of either the entire disk or just a partition is very, very small, the very first stage of the bootloader also has to be very small which translates into the bootloader being very dumb. This stupidity is normaly worked around by having the first stage of the bootloader seek a preprogrammed sector on the disk, loading the second stage of the bootloader contained therein and passing control to it. What this means is that once the first stage of the bootloader gets written into the MBR, the file containing the second stage Must. Not. Be. Touched. Otherwise, the first stage will not be able to find it. [See footnote for aditional words of I-leaned-this-the-hard-way-just-like-you-now wisdom.] It is entirely possible that during the resizing of the NTFS the resizing program moved the second stage bootloader. Footnote: In the case bootloader is single-stage, like LILO is, the system operates in a similar way. Instead of searching for the second stage bootloader, LILO is searching a specific array of disk sectors for the Linux kernel. For this reason, in every case that the kernel gets changed, LILO has to be rewritten into the MBR so that the new kernel can be found. Footnote.2: You know, it may be possible to get around this problem by writing the contents of the new file into the old file. ((cat newfile oldfile) instead of (cp newfile oldfile)) However, the contents would have to be of the same length and you would have to rely on the filesystem to not move the files around (I think ext3 does move files (reallocate the sectors for the file) in this case but ext2 does not move them; ext3 can be changed into ext2 by turning off the journal). -- You don't need an AI for a robot uprising. Humans will do just fine. --Skynet -- http://linuxfromscratch.org/mailman/listinfo/lfs-support FAQ: http://www.linuxfromscratch.org/lfs/faq.html Unsubscribe: See the above information page
Re: [lfs-support] help, i hosed my windows partition
One other thing, although it qualifies as a false hope: it just may be possible, at least theorethically, to recover most or all of the contents of the NTFS partition. So if you did manage to nuke the few starting sectors of your NTFS partition, do not lose hope just yet - unless the damage hit a critical part of the filesystem (which is very likely - it did hit the start of the partition, after all), it should be possible to extract most or even all files and directories. Although there are no guarantees - a part of some file could have been written over, or a directory may have lost some or all of its contents. Note that this method relies on having either a library or a program available that can perform the appropriate functions. I do not know of any that exist right now, especially for NTFS, but if you have something very important that you have not backed up somewhere else, maybe either look around for such a program or keep on to the image file of the damaged filesystem (partiton) until such a program gets written (because it eventually will). -- You don't need an AI for a robot uprising. Humans will do just fine. --Skynet -- http://linuxfromscratch.org/mailman/listinfo/lfs-support FAQ: http://www.linuxfromscratch.org/lfs/faq.html Unsubscribe: See the above information page
