Recover from a PVR-harddrive

[bos]

I got a Thompson PVR with a 160GB harddrive (IDE) that's got a dropped partition table. The drive itself seems to be without errors, and the data seems to be intact. But due to the drop of the partition table the PVR cannot read the contents anymore, and I've got two own made movies on it that I'd like to extract.

I replaced the drive with an empty 160GB drive and let the PVR format it, to get a grip on what filesystem is on it. Investigating on my computer the drive got two partitions, type Linux and Linux Swap. The former seems to have ext3 on it, but it's unable to mount. I recall an old memory saying that PVR usually run their drives with a raw partition.

Question: what turns can I take to make the harddrive readable by the PVR again? Because obviously I cannot extract anything useful from it due to the filesystems.

[data-medics]

Try a program like UFS Explorer. It can read pretty much any filesystem and extract files.

[Dmitri]

I got a Thompson PVR with a 160GB hard drive
...
due to the drop of the partition table the PVR cannot read the contents anymore

I recall an old memory saying that PVR usually run their drives with a raw partition.

Most likely the latter is true, usually such devices have no file system in the traditional meaning of this word. I say "most likely" because we mostly work with DVRs, but that's not something terrible, as due to the broad diversity, nearly each of them is like totally unknown device, which require a research to go on.

Question: what turns can I take to make the harddrive readable by the PVR again? Because obviously I cannot extract anything useful from it due to the filesystems.

Quite likely nothing that would be at least somehow close to easy. We regularly get DVR hard drives, which have been initialized in Windows or formatted in the device, but recreating the metadata on them from scratch is likely to require insane amount of time.
Much more reasonable approach here is to analyze the internal recording format and develop a custom software to extract the videos.

If necessary, we can look into this job and should be able to recover the movies remotely. Please check your PM.


P.S.
Also if you are installing the disk back into the PVR from time to time, I'd recommend to create a full sector-by-sector image of it first just to stay on the safe side.

[fzabkar]

@bos, why not record a small video on your 160GB drive and then examine the file system with a disc editor? You could then upload the file, or a portion of it. Alternatively, does the PVR allow you to export your videos to a flash drive?

[Dmitri]

why not record a small video on your 160GB drive and then examine the file system with a disc editor?

bos, if the videos you've mentioned are indeed irreplaceable, then I'd recommend you to not even think about writing anything to the source hard drive.

Besides the data you're after (or a part of it) can be simply overwritten, that can also add to the logical damage, which is already present at the moment.
Unless proved otherwise, I'd suggest that your PVR works the same way as DVRs do. Considering that scan yielded no results and you see only one partition, it's reasonable to suggest that partition is the system one and remaining space is likely "raw". For this reason results of writing on the hard drive are unpredictable, i.e. it may happen that PVR will initialize or format the drive it will consider new, it can erase calendar and so on.

The only way you can do such experiment is if you have created a full image and sure you will be able to deploy it if necessary.
But even after that most likely you won't find any files and will be able to upload partial images (sector ranges) only and that is not the worst idea to confirm the data format used in the Thompson PVR you have. BTW, chunks of data taken without writing anything will be OK as well.

[fzabkar]

why not record a small video on your 160GB drive and then examine the file system with a disc editor?

bos, if the videos you've mentioned are indeed irreplaceable, then I'd recommend you to not even think about writing anything to the source hard drive.

Sorry, I meant the "empty" 160GB drive, not the patient.

[bos]

Thanks for the input. The source drive is already backed up (sector-copy) and put on the shelf until further notice. I'm playing around with the drive image, but since I'm only familiar with DR from drives with filesystems, this one is a tough one. (I run a small DR company in my spare time)

The tip about recording a small movie is a good one. I did this yesterday just to verify that the DVD-burning is still working but I had not thought about investigating the drive for data. This might in fact be my best shot as for now.

I'm thinking of contacting Thompson requesting information how the data is stored on the drive. I'm not really expecting an answer, but it's worth a shot.