[Freedos-user] FDISK Format
Boy was I having fun getting my multi-boot flash drive to off of numerous operating systems. That is, until I accidentally blew away a fairly large partition. Yes, it was a careless and potentially costly mistake. Fortunately much of the data was backed up, but not all of it. I did this dirty deed with FreeDOS 1.0 FDISK format, on an approximately 30 GB FAT32 partition. I immediately looked at unformat, but I noticed that the message displayed after running format was something like unformat data not saved or ..unavailable. The format process was extremely quick, like maybe 5 seconds or less. There seems to be a wide variety of data recovery products that profess to work on FAT32 partitions after a format. But before I download, buy, try something out: 1. To those who know this OS and the nuances of what FreeDOS's format actually does, do you have any particular suggestions? 2. Anything I should avoid? Any data recovery programs recommended or that I should avoid (i.e. might make the situation worse)? I have used FreeDOS for numerous tasks in recent years. Thanks for the great program, and any constructive suggestions you can offer are greatly appreciated. -- SF.Net email is Sponsored by MIX09, March 18-20, 2009 in Las Vegas, Nevada. The future of the web can't happen without you. Join us at MIX09 to help pave the way to the Next Web now. Learn more and register at http://ad.doubleclick.net/clk;208669438;13503038;i?http://2009.visitmix.com/___ Freedos-user mailing list Freedos-user@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/freedos-user
Re: [Freedos-user] FDISK Format
Hi! I did this dirty deed with FreeDOS 1.0 FDISK format... I immediately looked at unformat, but I noticed that the message displayed after running format was something like unformat data not saved or ..unavailable. The format process was extremely quick, like maybe 5 seconds or less. Indeed. You can try FORMAT /Z:UNFORMAT X: or similar, but format with saving unformat data would be, say, 15 seconds compared to your format in 5 seconds. Much slower than a full format with surface scan and wiping of data clusters, of course. And indeed much of your data should still be there. What you probably did was delete a partition and create a new partition - maybe of same size and type - at more or less the same location. Still FORMAT noticed that the partition was new, so it did not save unformat info: It only made an empty root directory, marked all clusters as free, and declared the disk to be formatted then. This would give you good chances to find back a fair amount of your data as soon as you have gathered enough skills and tools to un-zombie and undelete everything. Maybe you had unformat info from before you did all this, but it would only be useful if it would be fairly fresh. If many file locations etc changed since saving the data, unformatting will actually do more damage than repair! It is hard to find out what can be done and when. If you really want to try your best to get back your data, the FIRST thing to do is make a diskimage of the whole stick and backup that. Then you can bring back the state at which you start the repair attempts as often as you want, and find out how to repair more and more, avoiding the risk of breaking things more / making them unrepairable while trying to repair. If your partition had exactly the same size, type and location before and after the incident, then only your root directory is really gone. The other direct sub- directories still float around as unnamed zombies, and you can undelete as many files and subdirectories as your luck allows after you undeleted those. However, unfortunately, FreeDOS UNDELETE cannot un-zombie, so you would have to use a disk editor or some more fancy undelete tool for the subdirectories directly under the root directory. Undeletion also depends on two things: It cannot deal well with fragmented files, and it cannot know which things can really be undeleted. Sometimes it can happen that you have several candidates which are all at the same or at least overlapping space of your disk. If you undelete the wrong candidate, you cannot undelete the other candidate any more - while only one candidate will have useful data inside afterwards. Well in FreeDOS undelete you are a bit safer, maybe: It does not only have classic undelete where you give back a deleted file his filename. It also has extract style: There you COPY the data of a deleted file to ANOTHER drive, as if the file was not deleted. THAT works even with overlapping files, but you have to think and type more on the command line. Please read the documentation of UNDELETE for details :-). I hope somebody can also point you to other nicer and more fancy undelete tools. In particular, quite a few seem to do content based undelete. In other words, they scan the disk for beginnings of JPEGs and other known file types and then fetch the whole file, a bit like extract style of FreeDOS UNDELETE but, as said, guided by remaining file contents. There seems to be a wide variety of data recovery products that profess to work on FAT32 partitions after a format. But before I download, buy, try something out: 1. To those who know this OS and the nuances of what FreeDOS's format actually does, do you have any particular suggestions? There are no really undelete / unformat relevant FreeDOS specific properties of FAT32 I could think of right now, but I guess if you HAD unformat data then it MIGHT be that ours does not follow exactly the format of MS DOS UNFORMAT. I did try to follow specs about unformat data when adding unformatability and unformatting to FORMAT, though, where available. 2. Anything I should avoid? Any data recovery programs recommended or that I should avoid (i.e. might make the situation worse)? Anything CAN make the situation worse, so depending on your data and resources, a backup of a full disk image of the raw disk is always a good idea. Even if it is only because disk space is cheap today and you may find a cool and easy to use unformat-all tool in the future, at some time, maybe by accident :-). You can also search the web for howto and best practice docs about data forensics, because trying to make sense of damaged data is exactly that. Many people do it and many people have tools around. However, high cost tools do not necessarily do anything better than low cost or manual repair. Please keep us updated about your attempts, and maybe give some more details on how exactly things broke and which type of data was backed up and which type of
Re: [Freedos-user] FDISK Format
Eric (and all), The good news is that the data on this partition had been saved prior to this debacle. I had made very few changes there recently. I saw that the format program indicated that the unformat data had not been saved, and I guessed that this was because the data size (~15 GB? on a 30 GB partition) may have been bigger than the remaining available space on the partition? I did try running unformat and the error I received was that the drive letter was out of range. Now, this gets back to what I was doing in the first place. I experiment periodically with booting different OSs from a USB stick. Usually, I see the device names and am extremely careful, but in this case the D: partition just so happened to be the D: on my laptop and not the one I thought I was formatting (on the USB flash drive). Of course I saw the 30 GB size listed next to the WARNING! message, only seconds after I pulled the trigger. Is it possible that if I ran the unformat command from a fresh FreeDOS install on the same disk that it would work? I tend to doubt this because, as I already explained, the message returned with the format process was something like unformat data not saved. Still, I am thinking that this unformat drive letter out of range error may be related to the fact that I was attempting to run unformat from the flash disk. I'm leaning in the direction of buying GetDataBack. There is a free demo which will indicate whether the product will recover my files. I may have to do plenty of reorganizing but that's more than a fair price for stupidity. Any dangers of running (from FreeBSD or Linux), say, dd=/dev/(partition I screwed) of=/dev/(other drive)? Is a 512 block size OK for that? I assume that this is what you meant regarding saving a backup disk image. --- On Mon, 12/8/08, Eric Auer [EMAIL PROTECTED] wrote: From: Eric Auer [EMAIL PROTECTED] Subject: Re: [Freedos-user] FDISK Format To: [EMAIL PROTECTED], freedos-user@lists.sourceforge.net Date: Monday, December 8, 2008, 1:23 PM Hi! I did this dirty deed with FreeDOS 1.0 FDISK format... I immediately looked at unformat, but I noticed that the message displayed after running format was something like unformat data not saved or ..unavailable. The format process was extremely quick, like maybe 5 seconds or less. Indeed. You can try FORMAT /Z:UNFORMAT X: or similar, but format with saving unformat data would be, say, 15 seconds compared to your format in 5 seconds. Much slower than a full format with surface scan and wiping of data clusters, of course. And indeed much of your data should still be there. What you probably did was delete a partition and create a new partition - maybe of same size and type - at more or less the same location. Still FORMAT noticed that the partition was new, so it did not save unformat info: It only made an empty root directory, marked all clusters as free, and declared the disk to be formatted then. This would give you good chances to find back a fair amount of your data as soon as you have gathered enough skills and tools to un-zombie and undelete everything. Maybe you had unformat info from before you did all this, but it would only be useful if it would be fairly fresh. If many file locations etc changed since saving the data, unformatting will actually do more damage than repair! It is hard to find out what can be done and when. If you really want to try your best to get back your data, the FIRST thing to do is make a diskimage of the whole stick and backup that. Then you can bring back the state at which you start the repair attempts as often as you want, and find out how to repair more and more, avoiding the risk of breaking things more / making them unrepairable while trying to repair. If your partition had exactly the same size, type and location before and after the incident, then only your root directory is really gone. The other direct sub- directories still float around as unnamed zombies, and you can undelete as many files and subdirectories as your luck allows after you undeleted those. However, unfortunately, FreeDOS UNDELETE cannot un-zombie, so you would have to use a disk editor or some more fancy undelete tool for the subdirectories directly under the root directory. Undeletion also depends on two things: It cannot deal well with fragmented files, and it cannot know which things can really be undeleted. Sometimes it can happen that you have several candidates which are all at the same or at least overlapping space of your disk. If you undelete the wrong candidate, you cannot undelete the other candidate any more - while only one candidate will have useful data inside afterwards. Well in FreeDOS undelete you are a bit safer, maybe: It does not only have classic undelete where you give back a deleted file his filename. It also has extract style: There you COPY the data of a deleted file to ANOTHER drive, as if the file was not deleted. THAT works even
Re: [Freedos-user] FDISK Format
J wrote: Any data recovery programs recommended or that I should avoid (i.e. might make the situation worse)? The first place I would post such a question is here: [EMAIL PROTECTED] DFSee can do some amazing things with partition tables and contents. And the author is there to help, including personal help in the form of custom scripts. And since the CD boots FreeDOS he has some understanding of that. I think everyone who works with drives should have this. And it is try-before-buy. Ray -- SF.Net email is Sponsored by MIX09, March 18-20, 2009 in Las Vegas, Nevada. The future of the web can't happen without you. Join us at MIX09 to help pave the way to the Next Web now. Learn more and register at http://ad.doubleclick.net/clk;208669438;13503038;i?http://2009.visitmix.com/ ___ Freedos-user mailing list Freedos-user@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/freedos-user
