Post by thread:[TECH] Truncated file recovery

Hi, I have a portable MPEG2 video recorder which records on FAT32 formatted CF32 cards. While I was out with my bike I recorded everything, as usual. Unfortunately a short power interruption has caused one file not to be closed, and now it appears as being 0 bytes long. However, a lot of data was recorded there, and is incidentally the data I was most interested in. I have tried with File Scavenger, with Easy Recovery, I have Googled for other utils but found nothing that seems that may help. Is there any utility or way to get the data back from that truncated file? I was thinking to open the file and set its length to an arbitrary high value.. but would that work? Of course I am currently avoiding any operation (such as CHKDSK /f ) that would modify the original device. Thanks. Mario

{Quote hidden}> > Hi, > I have a portable MPEG2 video recorder which records on FAT32 formatted > CF32 cards. > While I was out with my bike I recorded everything, as usual. Unfortunately > a short > power interruption has caused one file not to be closed, and now it appears > as being > 0 bytes long. However, a lot of data was recorded there, and is > incidentally the > data I was most interested in. > > I have tried with File Scavenger, with Easy Recovery, I have Googled for > other utils > but found nothing that seems that may help. > > Is there any utility or way to get the data back from that truncated file? > I was > thinking to open the file and set its length to an arbitrary high value.. > but would > that work? > > Of course I am currently avoiding any operation (such as CHKDSK /f ) that > would modify > the original device. > It depends on your recorder device. If you take a closer look at the whole recording operation, device reads from camera and saves the data to specified location. In your case your location is a CF card and when the power is interrupted device stopped reading from camera thus couldn't complete the last headers and structure of th file etc. You need to get inner details of your recorder because afaik there is no general approach to this situation. Device may use some portions of internal memory as a buffer or it may directly write to CF card. Usually low resolution data is written directly to external storage but when the quality increases then write speed to card might not catch up with the data coming from the camera sensor itself, like HD. Another approach would be to get an binary image of your card so that you can play with it without corrupting the original data. If you are lucky your device directly writes to CF card (without a buffer) and maybe you can extract some data from there.You will need to create an identical custom video file which will have valid headers and structure also same in data size.After that you can try to swap the data parts of your stuff and the custom created one. If you can provide additional information about your recorder I am sure people here will try to figure something out.

First off, I suggest using WinHex to generate an image of the device in question. WinHex also has some FAT32 diagnostic features that can help you. Basically, you have to (either programatically or manually) trace the cluster chain of your file until you get to a point where the next cluster in the chain is either invalid or not removed from the list of free clusters, indicating that the FAT management software stopped working. All the data up to that point should be fine. Then you can manually update the FAT entry for the file, or more simply, just extract all the data in the cluster chain into a file. - Marcel On Sun, May 9, 2010 at 1:12 PM, Electron <spam_OUTelectron2k4TakeThisOuTinfinito.it> wrote: {Quote hidden}> > Hi, > I have a portable MPEG2 video recorder which records on FAT32 formatted CF32 cards. > While I was out with my bike I recorded everything, as usual. Unfortunately a short > power interruption has caused one file not to be closed, and now it appears as being > 0 bytes long. However, a lot of data was recorded there, and is incidentally the > data I was most interested in. > > I have tried with File Scavenger, with Easy Recovery, I have Googled for other utils > but found nothing that seems that may help. > > Is there any utility or way to get the data back from that truncated file? I was > thinking to open the file and set its length to an arbitrary high value.. but would > that work? > > Of course I am currently avoiding any operation (such as CHKDSK /f ) that would modify > the original device. > > Thanks. > > Mario > > -

I do not understand btw why do they use FAT filesystem nowadays. You have to pay to Microsoft, plus the filesystem itself is rubbish based on 20 year old technology with no recovery option. People should start using a modern journaling filesystem for these large flash disks. I know, FAT is better suit to small micros as there is no need to calculate too much, however, if a mibile phone can play 3D games and if a digital camcorder can include useless picture effects then they could implement a proper filesystem driver too. Tamas On Mon, May 10, 2010 at 10:51 PM, Vitaliy <.....piclistKILLspam@spam@maksimov.org> wrote: > Electron wrote: > > I have a portable MPEG2 video recorder which records on FAT32 formatted > > CF32 cards. > > While I was out with my bike I recorded everything, as usual. > > I would love to see a picture of your setup. Especially the mounting > hardware. > > Vitaliy > > -

On Tue, 2010-05-11 at 07:09 +0100, Tamas Rudnai wrote: > I do not understand btw why do they use FAT filesystem nowadays. You have to > pay to Microsoft, plus the filesystem itself is rubbish based on 20 year old > technology with no recovery option. People should start using a modern > journaling filesystem for these large flash disks. Name one? What journaling filesystem would you use that gives the benefits of FAT32, without paying Mickeysoft? Remember, most people use windows, so any file system you use MUST be supported natively by windows (no installing stuff to get it working). That rules out pretty much all file systems other then FAT/exFAT and NTFS. Guess who you have to pay to use NTFS? The fact is there is NO other viable option then FAT. As horrible as you think it is, it's what we've got. Frankly, FAT works very well for flash cards. The only real limitation that is routinely hit these days is the max file size, hence the creation of exFAT. TTYL

Herbert Graf wrote: > On Tue, 2010-05-11 at 07:09 +0100, Tamas Rudnai wrote: >> I do not understand btw why do they use FAT filesystem nowadays. You >> have to pay to Microsoft, plus the filesystem itself is rubbish >> based on 20 year old technology with no recovery option. People >> should start using a modern journaling filesystem for these large >> flash disks. > > Name one? What journaling filesystem would you use that gives the > benefits of FAT32, without paying Mickeysoft? > > [...] > > Frankly, FAT works very well for flash cards. It's been a long time, but IIRC there were quite a number of tools around to do semi-automated recovery on FAT/FAT32 disks back in the days. They should still be out there. Gerhard

On Tue, May 11, 2010 at 3:35 PM, Herbert Graf <.....hkgrafKILLspam.....gmail.com> wrote: > Remember, most people use windows, so any file system you use MUST be > supported natively by windows (no installing stuff to get it working). > That rules out pretty much all file systems other then FAT/exFAT and > NTFS. > No, you can write drivers... So you do not need to be supported by drivers on your Windows installation disks as it can be installed any time. Also there are other options, like providing Samba instead of raw FS access... In my opinion it is just a laziness from the camcorder manufacturers not to thinking about alternatives.

On Tue, May 11, 2010 at 5:02 PM, Gerhard Fiedler <EraseMElistsspam_OUTTakeThisOuTconnectionbrazil.com > wrote: > It's been a long time, but IIRC there were quite a number of tools > around to do semi-automated recovery on FAT/FAT32 disks back in the > days. They should still be out there. > Back in DOS times I was doing hard drive recovery service. Manual or automatic tools, does not matter as most of the times the client already tried to recover the files by themselves knowing nothing about it. And it includes even formatting the disk! I mean, how could you recover files after that? Maybe with a military grade analyser that works on the slack magnetic fields or something :-) Anyway, I think a filesystem should be fault tolerant -- forgetting unmounting the disk before removing it, or power fail or ESD or even Software bug should not cause loss of everything or huge bunch of files. maybe portion of your data would be lost -- uncommitted data -- but the old version of the file should be still there anyway. Theoretically you have two copy of the FAT in FAT FS which is exactly for this reason, but that does not really help in practise. At least that is my experience. Tamas > > Gerhard > -

On Tue, 2010-05-11 at 17:18 +0100, Tamas Rudnai wrote: > On Tue, May 11, 2010 at 3:35 PM, Herbert Graf <hkgrafspam_OUTgmail.com> wrote: > > > Remember, most people use windows, so any file system you use MUST be > > supported natively by windows (no installing stuff to get it working). > > That rules out pretty much all file systems other then FAT/exFAT and > > NTFS. > > > > No, you can write drivers... So you do not need to be supported by drivers > on your Windows installation disks as it can be installed any time. Right, so for it to be MASSIVELY adopted you plan to write a driver for every OS out there and maintain it? I wish you luck. The fact is manufacturers are going to go with the easiest route. The easiest route at minimum is to choose a file system that is supported by the vast majority of machines out there. The vast majority of machines support FAT and NTFS, there is no disputing that. > Also there are other options, like providing Samba instead of raw FS > access... Wah?? That's even worse sounding. When I plug a device in my machine I WANT it to show up as a regular drive. Most manufacturers tend to agree with this position (Apple being the biggest outlier, and they get hammered for it alot). What are you envisioning anyways? I plug a flash card into a machine and it shows up as a network share or something? How does that benefit ANYONE? > In my opinion it is just a laziness from the camcorder manufacturers not to > thinking about alternatives. It doesn't matter if you label it lazy or not, the manufacturers are interested in making their products as easy to use for as little money as possible, that's the nature of the game. Farting around for no financial benefit is NOT what a company interested in making money is likely to do. TTYL

Herbert Graf wrote: {Quote hidden}> On Tue, 2010-05-11 at 17:18 +0100, Tamas Rudnai wrote: > >> On Tue, May 11, 2010 at 3:35 PM, Herbert Graf <@spam@hkgrafKILLspamgmail.com> wrote: >> >> >>> Remember, most people use windows, so any file system you use MUST be >>> supported natively by windows (no installing stuff to get it working). >>> That rules out pretty much all file systems other then FAT/exFAT and >>> NTFS. >>> >>> >> No, you can write drivers... So you do not need to be supported by drivers >> on your Windows installation disks as it can be installed any time. >> > > Right, so for it to be MASSIVELY adopted you plan to write a driver for > every OS out there and maintain it? I wish you luck. > > The fact is manufacturers are going to go with the easiest route. The > easiest route at minimum is to choose a file system that is supported by > the vast majority of machines out there. The vast majority of machines > support FAT and NTFS, there is no disputing that. > > >> Also there are other options, like providing Samba instead of raw FS >> access... >> > > Wah?? That's even worse sounding. When I plug a device in my machine I > WANT it to show up as a regular drive. Most manufacturers tend to agree > with this position (Apple being the biggest outlier, and they get > hammered for it alot). > > What are you envisioning anyways? I plug a flash card into a machine and > it shows up as a network share or something? How does that benefit > ANYONE? > > >> In my opinion it is just a laziness from the camcorder manufacturers not to >> thinking about alternatives. >> > > It doesn't matter if you label it lazy or not, the manufacturers are > interested in making their products as easy to use for as little money > as possible, that's the nature of the game. Farting around for no > financial benefit is NOT what a company interested in making money is > likely to do. > > TTYL > > agreed 100%

Thank You for all Your replies. I'm glad that my post has generated also some very interesting discussions on filesystems. I have bad news. I don't think that the file (being a proprietary format) is recoverable. As I didn't find any utility able to recover the truncated file, I tried to se the length of it manually, via some KERNEL32.DLL calls. Unfortunately, although it "formally" works like a charme, everything is zero'ed. In the end it will be easier for me to return there in that enduro track "paradise" and film it again. Vitaliy: unfortunately right now I have no working photocamera. Anyhow, this is what I use: http://www.dogcamsport.co.uk/hqr1-with-sony-hq1-bullet-camera-kit.htm The way I've fixed the camera is under the helmet's visor, to protect it. I have used normal (nylon?) ties. I'm using a RJ45 connector behind the helmet and normal Ethernet (shielded) cables till another RJ45 connector on the recorder side, which I keep on my pouch. It's a MPEG2 recorder and this is the best thing of it, for the rest it's quite troublesome as it heats way too much (and after about 1 hour it turns off by itself because of that), battery lasts about 80 minutes, but I am using a BatteryGeek auxiliary battery to fix the problem. It can record even on 32GB CF cards, so it's good for long rallies or whole enduro races. Cheers, Mario