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Ask Slashdot: What's a Good Tool To Detect Corrupted Files?
Volanin writes "Currently I use a triple boot system on my Macbook, including MacOS Lion, Windows 7, and Ubuntu Precise (on which I spend the great majority of my time). To share files between these systems, I have created a huge HFS+ home partition (the MacOS native format, which can also be read in Linux, and in Windows with Paragon HFS). But last week, while working on Ubuntu, my battery ran out and the computer suddenly powered off. When I powered it on again, the filesystem integrity was OK (after a scandisk by MacOS), but a lot of my files' contents were silently corrupted (and my last backup was from August...). Mostly, these files are JPGs, MP3s, and MPG/MOV videos, with a few PDFs scattered around. I want to get rid of the corrupted files, since they waste space uselessly, but the only way I have to check for corruption is opening them up one by one. Is there a good set of tools to verify the integrity by filetype, so I can detect (and delete) my bad files?"
is urgency. Corrupted files have the ability to detect urgency and your discovery of them will come in a form compatible with the laws of Murphy.
2000-2001 MAF-Soft http://www.maf-soft.de/
The version I have is v1.0.3.102
It can scan single mp3s and entire folders structures for defects and logs everything if you wish. It will give you a percentage of how good the file is.
Depending on the damage you may be able to fix headers and chop off corrupted tag info with something like a MP3Pro Trim v1.80.exe
Obama's legacy: (N)othing (S)ecure (A)nywhere and (T)error (S)imulation (A)dministration
Author here:
> Last backup August.
Yes, that was silly of me.
> Thinks there is a way to detect generic file corruption
There is no way to detect generic file corruption. But there is a way to detect specific filetype corruption. For example, I already found mp3val, that is able to scan all my mp3 and check for file integrity, and even fix a few kinds of corruption (such as unmatching bytes in the header and sound chunks). Maybe with the right set of tools, I might also detect (or even fix) my corrupted pictures, movies and books as well.
If I clone myself, can I call it a thread?
If a girl winks to us, can I call it a race condition?
I'd be asking myself why lots of files became corrupted from one dodgy file system event. Assuming HFS works like file systems I'm more familiar with, it will allocate sequential blocks for files wherever it can. This means that a random filesystem splat is really unlikely to corrupt loads and loads of files. You might expect a file system corruption to cause a load of files to go missing (if a directory entry is corrupted) or corrupt a few files, but not put random errors into loads of files.
I'd check to see whether files I was writing now get corrupted too. It might be dodgy disk or RAM in your computer.
The above might be complete paranoia, but I'm a paranoid person when it comes to my data, and silent corruption is the absolute worst form of corruption.
For next time, store MD5SUM files so you can see what gets corrupted and what doesn't (that is what I do for my digital picture and video archive).
Every man for himself, all in favour say "I"
Well...
My first suspicion would be that the filesystem is messed up, not the actual files. Unless s/he had a lot of pending writes to all of these files, there is no reason that something should have actually overwritten or garbled them when the power shut down. Much more likely was an impending or in-progress write to the filesystem's tables, which has affected where it thinks all the files' pieces are stored. And if that is the case, date modified and size may be irrelevant because those are going to be reported by the filesystem.
Aside from trying to read back sector-by-sector data and assembling them, however, I don't know that there's a remedy.
I vote based on politicians' actions, unless contrary to my preconceptions. Often wrong, never uncertain. #iamthe99%
Author here:
Ok, I could deal with the loss of some unique videos and pictures from travels... but now that you mention the porn... *weep*
If I clone myself, can I call it a thread?
If a girl winks to us, can I call it a race condition?
Alright now I'm afraid I can't help with your verify problem but I do have one piece of solid advice: get rid of Paragon HFS immediately!
It is a truly shoddy piece of software that as of version 9.0 has a terrible bug that will cause it to destroy HFS+ filesystems. Google "paragon hfs corruption" and you will see many many horror stories from people who just plugged a Mac OS X disk into a Windows machine w/ Paragon HFS and then discovered the entire filesystem was hosed. In my dual-boot win/mac setup I replaced my copy of MacDrive with a trial version of Paragon HFS 9.0 from their website and every single one of the six HFS+ disks I had connected internally were damaged. Disk Utility couldn't do a thing and I had to buy a program called Diskwarrior to even begin to recover data. I ended up losing two disks worth of files anyway.
http://www.mac-help.com/t12137-opened-hfs-drive-win7-paragon-hfs-now-wont-boot.html
http://www.wilderssecurity.com/showthread.php?t=299306
http://hardforum.com/showthread.php?t=1677099
http://www.avforums.com/forums/apple-mac/1509344-hfs-super-block-not-found.html
whew! Anyway the pain I went through after that software very nearly ruined my life was so great, I don't want it to happen to anyone else. According to their own website 9.0 has this awful bug but they fixed it in 9.0.1. Evidently the trial download on the main page is still for version 9.0 and still has the disk destroying bug! Any software company that releases a filesystem driver with this terrible a bug (not to mention the numerous reports of BSODs and other relatively minor problems) clearly has terrible quality assurance and simply can't be trusted.
That is a good thought, and photorec does an excellent job of finding pictures and videos by searching through your sectors - definitely worth a try.
http://www.cgsecurity.org/wiki/PhotoRec_Step_By_Step
Every man for himself, all in favour say "I"
mplayer can detect corrupted movie and audio files find . -name '*.mov' -exec mplayer -msglevel all=6 -speed 100.0 -framedrop -nogui -nolirc -cache 8192 -tskeepbroken -ao null -vo null {} \; | grep Warning! > $1.txt Change the *.mov as appropriate.
<infomercial>its JUST. THAT. EASY folks!</infomercial>
The identify program is a member of the ImageMagick(1) suite of tools. It describes the format and characteristics of one or more image files. It also reports if an image is incomplete or corrupt.