Broken track files from old corrupted HDD

[dukeofurl]

Hi guys, as a Christmas present to myself, I recently hired a data recovery service to try and recover data from the old defunct nonworking HDD from my first computer circa 1993. The recovery service had better luck than I had with my amateur data recovery efforts, and they sent over a file list to show what they recovered from the drive.  Judging from the file types, some of my old Stunts tracks were recovered!

The catch is, that the HDD partition was damaged and the recovery included recovering a mix of good files and damaged/partial files.  I'm yet to receive my recovered data back, but looking at the stunts files I've seen in the file listing, the vast majority of the stunts track files have messed up names, such as "_rack1" instead of "track1", which is a nomenclature I've seen before when recovering damaged (and ultimately nonworking) files from floppy disks. So I assume many of my stunts tracks will be among the damaged/partial files from the recovery. 

When I get the files back (in a few days), I will certainly test them and may upload them here, but I guess I'm wondering - if I have a partial file, might there be any conceivable way to repair it so that I could see what remains of it within Stunts?  Like maybe combining the data I have from the partial file with data from a working stunts track?  In any case, I suppose I'll check that out to see what can be done.  Expecting to actually have the data back in a few days...

[dreadnaut]

if I have a partial file, might there be any conceivable way to repair it so that I could see what remains of it within Stunts? 

Valid track files from Stunts should all be 1802 bytes. Hard drive sectors at the time were around 512 bytes, if I remember correctly. So four sectors to a track: partially recovered files are possible.

If your tracks are incomplete, there'll be a sector missing, could be terrain or track. You'll need a bit of guesswork to understand which chunk is missing, an hex editor to fill it with zeros, and then we'll see what Bliss or Stunts make of it

[dukeofurl]

OK! I got the files back today.  I sorted all the stunts tracks/highscores etc into a directory. Some of the names seem messed up but there are also files that don't have messed up names.

Anyway I tried to load about 10 of them, including several with good looking file names, and a few with bad ones, and none of them worked, and they either wound up freezing or crashing stunts and/or dosbox so things aren't looking too great lol.  Not sure how to edit these in a hex editor to try and make them somewhat loadable, but I'm throwing them up here in case anyone wants to play around with recovering these to a semi useable state   They might also just be junk data at this point?  Some of the files recovered from this drive, such as ordinary readme.txt files included with software just show up as gibberish when they are opened... however there are some good working files as well...

Anything that might become loadable that appears to be an incomplete track, I'll happily try to finish into something complete-able.

[Foxpup]

So, I ran an entropy test (results in attached .csv file) on all your .trk files to quickly assess which ones, if any, are indeed just random garbage, and the answer regrettably appears to be "almost all of them". Normal Stunts track files have an entropy of around 2 bits per bytes, while these recovered files average over 6 bits per byte, with many close to the limit of 8 bits per byte (pure randomness). Two files (~F2249.TRK and ~F2265.TRK) have 0 entropy as they are completely blank. There are some files in between these two extremes, indicating that they may be candidates for more advanced recovery, but almost all of them appear to just be blocks of random garbage with strings of null bytes in between. Only one file (~F2323.TRK) seems to contain a "valid" Stunts track, in that it contains valid track pieces and loads correctly in the in-game editor, though it's just a collection of seemingly random track pieces filling two-thirds of the map, with the remaining third of the map completely blank. I don't think you can do much with it.

ETA: Some of these files seem to contain regular data structures aligned to 16-byte boundaries, which appear to be neither random garbage nor track data. Possibly recoverable data from other files entirely? ETA: Confirmed: ~F2269.TRK definitely isn't a Stunts track: it's a perfectly intact fragment of your SYSTEM.INI file! If you had any personal or sensitive information on this PC, some of it may be in these files, so you may want to take it down.

[Matei]

and none of them worked,

They work with Track Blaster. Pictures attached with ~F2269. Looks good. I guess I can't drive on it though.

[dukeofurl]

So, I ran an entropy test (results in attached .csv file) on all your .trk files to quickly assess which ones, if any, are indeed just random garbage, and the answer regrettably appears to be "almost all of them". Normal Stunts track files have an entropy of around 2 bits per bytes, while these recovered files average over 6 bits per byte, with many close to the limit of 8 bits per byte (pure randomness). Two files (~F2249.TRK and ~F2265.TRK) have 0 entropy as they are completely blank. There are some files in between these two extremes, indicating that they may be candidates for more advanced recovery, but almost all of them appear to just be blocks of random garbage with strings of null bytes in between. Only one file (~F2323.TRK) seems to contain a "valid" Stunts track, in that it contains valid track pieces and loads correctly in the in-game editor, though it's just a collection of seemingly random track pieces filling two-thirds of the map, with the remaining third of the map completely blank. I don't think you can do much with it.

ETA: Some of these files seem to contain regular data structures aligned to 16-byte boundaries, which appear to be neither random garbage nor track data. Possibly recoverable data from other files entirely? ETA: Confirmed: ~F2269.TRK definitely isn't a Stunts track: it's a perfectly intact fragment of your SYSTEM.INI file! If you had any personal or sensitive information on this PC, some of it may be in these files, so you may want to take it down.

Thanks for the heads up.  I'm not that concerned about personal/sensitive information being in these files.  This computer is so old that it predates things like us using the internet for financial transactions. And even if there was something there, it would for the most part be completely obsolete, as things like the banks we used to have accounts at 30 years ago simply don't exist in the current day, the people who used this pc don't live at the same addresses as back then, etc. Thanks for analyzing the files and letting me know its mostly junk data.  I did start to have that hunch when dragging a few of them into a text editor and seeing how the gibberish didn't look like the same type of gibberish as a valid trk file.  I'll leave the archive up for a little bit in case anyone here still wants to check them out for crazy recovery purposes but I won't leave it up forever.

By the way, the original stunts tracks that  come with the game are in here as well, I think with the first letter is generally missing such as _elens for Helens. That may be a source of comparison for how a file might be different from its original state in case there remains any commonality between the bad version of the original tracks in this archive and good versions of those files from a regular copy of stunts.  Or maybe it'll just prove the bad version is full of junk data and bits of other files and there is nothing to do lol

and none of them worked,

They work with Track Blaster. Pictures attached with ~F2269. Looks good. I guess I can't drive on it though.

Interesting. I've never used that program, but I'll run the files through them in case there is something that looks like a realistic segment of a track.

[dukeofurl]

And by the way, while it looks like these tracks from the HDD of this computer are probably not going to be that functional, just a reminder that I found and was able to backup a floppy disk that had valid working tracks my family made that were in most instances, even older than the pack of corrupt tracks.   https://forum.stunts.hu/index.php?topic=4200.0