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Hello, I stumbled across a very weird partition problem (from my experience this is top 5). Here's the situation: I have dual boot with Ubuntu and Windows 2000. Everything worked ...
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  1. #1
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    Dual Boot OK - windows partition BAD - linux OK !!


    Hello,
    I stumbled across a very weird partition problem (from my experience this is top 5).
    Here's the situation: I have dual boot with Ubuntu and Windows 2000.
    Everything worked OK until I reinstalled Windows. Dual boot does not seem to be harmed as I can boot on both just fine (grub)
    I did a format on C: (primary) and reinstalled windows and they went fine until I tried accessing my other HDs to get the rest of programs/data installed again.
    There's two physical disks and one of them has the problem.

    Before doing any work on Windows I downladed nvidia system drivers from linux (as I hadn't setup windows yet) and saved them on a FAT32 partition. (I don't know if that started anything, don't think so, but just mentioning it anyway).

    When I tried installing them I get an error message, some weird thing that the installation is corrupt or something, don't remember exactly and from there on I knew there was trouble ahead.

    When trying to browse the files on that partition I could see that some dirs where corrupt with the "usual" weird names on the folders, unrecognisable characters and all that. But not all were "corrupt", some were still ok.

    Now I boot into linux and surprise! Everything seems fine, dirs are there, folders perfect!

    My guess is that some partition information is corrupt but I can't understand the magical way in which linux-Ubuntu sees them fine.
    Is there some way I can pass the partition information that linux reads to windows?
    I don't want to do it through windows as that is probably much more trouble unless someone knows a method for that. Unfortunately windows is where I am good at so I need help with doing it from linux.
    Cheers.

  2. #2
    Linux Guru AlexK's Avatar
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    how big is this FAT partition? IIRC Windows XP/2K can't see past 32 gigs on a FAT partition, but Linux and pretty much any other OS can. i.e. Windows will create a such a large partition, but once you go over the "magic" 32 gig number, it can't differentiate between a file and a folder, hence the random corruption you see.

    From Linux, try burning stuff to cd/dvd and get rid of or backup any un-necessary stuff to bring the usage below 32 gigs perhaps around 30 or so.
    Life is complex, it has a real part and an imaginary part.

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    I had completely forgotten about that. There are two partitions 101:110GB respectively and the HD is a total of 250GB. Win2K can't even see such drives (past 127GB) and there's a registry entry that has to be added manually in order to be able to see it.
    Thing is this installation worked perfectly before but the 250 HD was added later after this registry fix was applied and I forgot that I did that. I was using this installation for more than a year but that's the first re-install I did on it.
    I went to windows and did the fix but it didn't change a thing. Probably I have to delete the HD info completely from the registry (or even do a clean install without the HD mounted) and then before using it I should apply the patch.
    Thanks very much for reminding me of it (or the similar 32GB problem).
    I will try later on and post the result. I hope it works as I don't have another HD to back up to with such empty space.

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    Here's what happened finally:
    You can't delete the HD registrations in normal mode so I went for safe mode. Bad mistake! NEVER DO THAT on a corrupt system!
    Apart from the funny blocks and colors while booting there was something definitely wrong while booting so I tried to stop it as soon as possible. Too late.
    All the "corrupt" folders were turned into 32KB files and a huge "FOUND" directory out of nowhere.
    So after giving a loud shout and deciding that in the end I "just" lost half a HD, so what, life goes on, procedure followed:
    1. Disabled mounting of said problematic HD from Ubuntu. (it was going on a very long list of renaming the files in "FOUND" so that couldn't be good, it probably wasn't that bad at the time but I just wanted the partition, FAT32, dir information whatever intact.)
    2. Re-installed Windows 2000 (that was the easy part. I had just done it so no worries there) and applied patch without the problematic HD installed. After installation of win, physically mounted the HD again.
    3. HD low level edit on the filesystem. Yep, that's right. I went into each and every one of the mis-repaired "file" entries and turned them in "directory" entries. That took about 4 hours and each time saving the original data on a single file, just in case.
    4. Marked "FOUND" as deleted, restarted several times and a chkdsk without fixing. It only found "Recycled" and "FOUND" as crosslinked and a final chkdsk with /fix
    5. Enabled again mounting of HD in linux to check readability.
    6. 6th coffee.
    7. After a long 7+ hours...Done! In the end I managed to recover ALL the "deleted-corrupt" entries and the system is running again with dual boot.

    PS1. This post in the end doens't have a lot to do with linux, but the problem started because of the dual boot situation, but linux didn't do anything wrong after all. Apart from finding one directory not empty and "recovering" 2-3 bogus files (I don't know why it did that without asking though) as well as the renaming of those trouble-false entries.
    PS2. So if anyone ever finds him/herself in a similar situation, here are my tips to get out of trouble.
    1. When re-installing Windows (2000/XP) on a large >127GB HD make sure you do the "EnableBigLba" registry fix, first thing after installation. It's a little entry in "HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\ atapi\Parameters" - "EnableBigLba"=dword:00000001
    2. Install the large HD after that fix.
    3. Dual boot is not harmed when reinstalling Windows 2000 on an alread dual-boot system. (Don't know about WinXP)
    4. Never, ever go into safe mode with a problematic disk if you care at all about your data.

    Good luck

  5. #5
    Linux Guru AlexK's Avatar
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    glad that you could get it fixed, and thanks for posting the solution to the problem so that the next poor soul to encounter it has some hints to try.
    Life is complex, it has a real part and an imaginary part.

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    Quote Originally Posted by Arheos
    All the "corrupt" folders were turned into 32KB files and a huge "FOUND" directory out of nowhere.
    .....
    3. HD low level edit on the filesystem. Yep, that's right. I went into each and every one of the mis-repaired "file" entries and turned them in "directory" entries. That took about 4 hours and each time saving the original data on a single file, just in case.
    4. Marked "FOUND" as deleted, restarted several times and a chkdsk without fixing. It only found "Recycled" and "FOUND" as crosslinked and a final chkdsk with /fix
    5. Enabled again mounting of HD in linux to check readability.
    So I have a similar problem, but I am wondering exactly what you did to low level edit the file system (what program you used, how to change entries from file to directory on the FAT32 file system, how to mark something deleted, etc) because I know I need to use a disk editor but most of the ones I have found use hex editing, and I don't know how to use that. I count myself lucky that my numerous google searches managed to get me to this thread!

    I also apologize if this is against some resurrection rule, but I am in true need and I am sure I am not the only one who wants to know how to fix this. In case you're wondering, I am comfortable using either Linux or Windows application to solve this. Please also assume that I know what I am doing except what I ask about, and don't classify me as a newb, etc etc.

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    Quote Originally Posted by TomT64
    So I have a similar problem, but I am wondering exactly what you did to low level edit the file system (what program you used, how to change entries from file to directory on the FAT32 file system, how to mark something deleted, etc) because I know I need to use a disk editor but most of the ones I have found use hex editing, and I don't know how to use that. I count myself lucky that my numerous google searches managed to get me to this thread!

    I also apologize if this is against some resurrection rule, but I am in true need and I am sure I am not the only one who wants to know how to fix this. In case you're wondering, I am comfortable using either Linux or Windows application to solve this. Please also assume that I know what I am doing except what I ask about, and don't classify me as a newb, etc etc.
    I tried going back to that procedure because it was some time ago and these things tend to (want to) be forgotten!

    WARNING: This is ONLY for the FAT32 system, NOT for NTFS!. Don't want anyone asking for explanations why they ruined their system. And I am no expert at stuff like that. I just taught myself ever since DOS was out. Had to do a lot of this freaking low level edit eversince!

    Here's my recollection:

    1. Program used (mostly): Runtime's DiskExplorer. The evaluation version allows you to write changes to the disk so that will do. Make sure it's on "Virtual Mode" and not "Direct Read/Write". You make changes, you even say "Write chages" but they're still virtual so they're not gone to the disk yet. Only on exit it asks the "scary" question: "Want to write changes? Data will be destroyed!"
    [I used it because it looked like DiskEdit from the old DOS Norton Utilities, displays Dirs and things in an easy to read manner and of course as Hex (you will need that) Text etc. No other reason, first to bump into really.]

    2. Use that (or whichever) and go to a dir with a normal view of the entries (Filename,Status,Type,Date etc.)
    You'll see lots of chopped up LFN filenames and lots of 8.3 names under each.
    It goes like this, only from the bottom up(!) i.e. when you see the 8.3 entry, the LFN is right above it, so in real disk data, before it. The LFN will takes up 32 bytes and if the filename is longer it will take up the previous 32 bytes and the previous and so on. But the 32 bytes are continuous only each character of the filename takes up two (2) bytes. That's for international characters and if you have such you will probably see gibberish. Much harder...

    3. The first byte of the 8.3 entry is the first character of the filename but the first byte of the LFN entry depends on the type filename/directory (maybe more classes...)
    [Values in Hex format]
    Filename=01
    Directory=41
    Deleted=E5

    When a file/dir is deleted both characters change to "E5".

    4. Locate the 8.3. and two rows above it you'll see the class character (most editors use 16 columns). If it's a deleted entry you'll have to change both 8.3 and LFN of course. If you want to switch from file<->dir, only the class.
    [You're not saying much about your problem so I assume this is the most important part for you. I am 99% certain there's nothing more to change to turn a "File" entry into "Dir" and vice versa. Assuming normal "attributes".]

    5. Now "Write changes" (if using aforementioned program). This way you will be able to virually access any directories that you "recovered" and check things first time around.
    Better exit each time you make changes (yes it took a long time!) so you can be sure you did the correct change. As I mentioned in my "recovery" post, after each change I kept a backup of the original bytes/entries just in case. Take a full backup if you can too, before ANY changes.

    That's all I can think of. If in doubt ask...
    Good luck and if you remember let me know of the level of success (I hope! )

    Keywords: deleted entries filenames directories corrupt recover recovered fat32 ntfs system windows win2000 win2k disk editor

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    Alright I will try what you suggested, but it may take a couple of weeks for me to get to it as I am very busy this week, Saturday is St. Patrick's Day, and then a week's vacation However I hope to be back after that and share with you the results. Here's hoping all goes well and I don't hit a snag.

    I do want to note that I tried Acronis Disk Director, a windows program, first and changed a few of the file entries into directories, then checked to see what happened. Now I realize that probably wasn't smart but I am pretty sure nothing else on the drive changed unless windows got sneaky (which is entirely possible). Inside the directories were gibberish filenames and directories. Also after hooking the drive up to try this (and before I tried it) the FOUND directory was gone. All the files in the root directory were still intact after everything I did, including hooking up the drive in the first place to the computer with Acronis on it. I never opened any of these files but I did open the directories that I made. If there's a problem with those directories, I am reasonably certain that I am ok with losing that data. If you think this might cause problems please let me know what you think may happen. Since that first test the drive has been set aside until such time as I either fix it or decide to wipe it out of impatience. Thanks to your reply I will wait a bit longer and try your method before being impatient.

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    Quote Originally Posted by TomT64
    I do want to note that I tried Acronis Disk Director, a windows program, first and changed a few of the file entries into directories, then checked to see what happened. Now I realize that probably wasn't smart but I am pretty sure nothing else on the drive changed unless windows got sneaky (which is entirely possible). Inside the directories were gibberish filenames and directories. Also after hooking the drive up to try this (and before I tried it) the FOUND directory was gone. All the files in the root directory were still intact after everything I did, including hooking up the drive in the first place to the computer with Acronis on it. I never opened any of these files but I did open the directories that I made. If there's a problem with those directories, I am reasonably certain that I am ok with losing that data. If you think this might cause problems please let me know what you think may happen. Since that first test the drive has been set aside until such time as I either fix it or decide to wipe it out of impatience. Thanks to your reply I will wait a bit longer and try your method before being impatient.
    Most of these automated recovery software solutions are too smart for their own good. Would be better if you didn't use any automated soft (from now on...), they try their best but with damaged goods, manual handling is better!
    This is new information you're giving me now. Gibberish dir and file names could be something else. Maybe a "broken" partition information or some other problem.
    I have come across a similar situation.
    Root dir ok and some other dirs seemed fine but many had gibberish names in the subdirs and some were even unreadable. But if the directory was corrupt, it was fully corrupt. There were no hit and miss filenames.
    After some low level searching it turned out that the directory structure/entries were "shifted" a specific amount of bytes (forwards or backwards, can't remember. It was more than 2 years ago and I can't remember whether it was a RAM failure that caused it or a partition break down and yes you can loose data from RAM failure.)
    I had to go through all the directory structures that were messed up and do the back-shifting. Any software I tried couldn't correct the partition problem -if it was one such- or couldn't identify the problem at all and just discarded the entries as corrupt. (That was a whole different problem and the procedure was MUCH more complicated.) Of course there was data loss at the end, mostly the last entries&data which was less than 5-10% of the total.
    My previous post could help if you find lots of directory entries turned to files and typical 32KB files in the FOUND directory but I don't know whether it can be of much help if you have a similar to the above situation.
    Still...best of luck.

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    Well the software wasn't automated, it simply let me use checkboxes to turn some of the "files" back into directories. But if it's only going to show me gibberish in each directory then I guess the data isn't recoverable (easily enough) after all.

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