Recovering "lost" Data

[Hairyloon 0]

A while back I bought a CCTV system for my house. It is nearly brilliant, but the bit by which it misses makes it rubbish.

The only identifying feature is the product number: DVR-MJ14

 

A few days back my lodger had an altercation with some thieves. I've been away, so he has been looking forward to viewing the footage, but it only has film from the past couple of days.

 

My guess is that the disk ran out and it has started overwriting, which would mean that the data is still on it, but I can't think how to access it.

It plugs into the computer via USB.

The disk has an unknown filesystem and it comes with its own software to view it.

 

Any ideas?

[Soundy 1]

The thing is, when you delete data, normally it's still there, but the index to it has been removed. Once you start writing new data to that space, though, the old data is replaced. There's is a very faint chance to restore some data after this , but every time it's overwritten, the chance narrows. If your machine is only keep two days, then every two days the old data is being overwritten again.

 

To have any chance at all, you'd need data recovery software that can read the file system format that your DVR is using, and you'd have to plug it into a computer that could read the disk structure. To get anything useful, it would have to recover enough pieces of the relevant files to put together coherent video clips... and the chance of doing that will also depend on the video format being used, whether a video can be extracted from little bits or not.

 

Just offhand, I would suspect you wouldn't be able to do this yourself with any readily-available software... you'd probably be a lot more likely to get something back by using a data recovery service. From my experience, you're probably looking at anywhere from $300 to $1000 for that... IF it's even going to be possible.

[Hairyloon 0]

The thing is, when you delete data, normally it's still there, but the index to it has been removed. Once you start writing new data to that space, though, the old data is replaced.

Yes, I knew that.

There's is a very faint chance to restore some data after this , but every time it's overwritten, the chance narrows. If your machine is only keep two days, then every two days the old data is being overwritten again.

The disk can store several weeks worth, if it has only overwritten a couple of days, there is a good chance the relevant data is still there.

The issue is getting a computer to recognise it.

[Soundy 1]

The disk can store several weeks worth, if it has only overwritten a couple of days, there is a good chance the relevant data is still there.

 

THis doesn't make sense - you previously stated:

"...it only has film from the past couple of days. My guess is that the disk ran out and it has started overwriting..."

 

If it will normally hold several weeks' worth of video, and this incident was only "a few days back", then it should have more than a couple days' worth, and it certainly shouldn't have overwritten your recent footage: unless there's something seriously wrong with the system, it should always overwrite the OLDEST footage.

[Hairyloon 0]

it should always overwrite the OLDEST footage.

That is certainly how I would have designed it. This would not be the first thing to make me think it is not well designed, though it is certainly the worst.

 

I don't know what has happened. My guess is that having filled the disk, it has reset and "wiped" the disk.

If that is what happened, then it is a really stupid design, but I can't think of another explanation.

 

But, unless you take a considerable effort to do so, when a disk is "wiped", it doesn't actually destroy the data, though, as you say, if it has been written over, it becomes very difficult to recover.

 

Maybe I am wrong, and it has just had a very busy few days that has filled up the disk.

 

Either way, I still want to find an alternative means of accessing it, as the interface they have provided is rubbish.

[tomcctv 187]

it should always overwrite the OLDEST footage.

That is certainly how I would have designed it. This would not be the first thing to make me think it is not well designed, though it is certainly the worst.

 

I don't know what has happened. My guess is that having filled the disk, it has reset and "wiped" the disk.

If that is what happened, then it is a really stupid design, but I can't think of another explanation.

 

But, unless you take a considerable effort to do so, when a disk is "wiped", it doesn't actually destroy the data, though, as you say, if it has been written over, it becomes very difficult to recover.

 

Maybe I am wrong, and it has just had a very busy few days that has filled up the disk.

 

Either way, I still want to find an alternative means of accessing it, as the interface they have provided is rubbish.

 

 

 

Hi its just ther way the dvr is......... made in mass and sold cheap. once the H/drive is full they format. it is another part of dvr specs that customers need to see or ask ....... is it 30 days recording or 30 days continuous recording.

 

as far as finding alternative accessing and new interface. that just cant be done with a $45 (without H/drive) dvr.

 

this is what a lot of guys try to get people to understand cheap mass produced dvrs do not work. i bet you spent more than $45 for 1 smoke detector in your home.