Talk:Undeletion

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[edit] Mac bias

I don't like how Macintosh's Trash can is mentioned before Microsoft's Recycle bin. I presume this is bias and therefore suggest we list them in alphabetical order (i.e. Recycle Bin before Trash can).—Preceding unsigned comment added by 201.141.183.13 (talk • contribs) 01:02, 25 October 2006

As far as I'm aware the feature was implemented on the Macintosh before it was in Windows. Besides, Macintosh Trash comes before Windows Recycle Bin alphabetically... --Safalra 19:09, 27 December 2006 (UTC)

Bill Gates's Microsoft Windows Recycle Bin comes before Steve Job's Apple Macintosh Trash Can.

[edit] NTFS undeletion

How is NTFS regarding undeletion?

Needs a list of undelete software, which OS it's for, which it runs under, and whether it is freeware/shareware/$ware and open-source or not.—Preceding unsigned comment added by 67.172.182.35 (Talk) (talk • contribs) 00:16, 15 December 2006

I also am disappointed there wasn't one. Now I am off to search google for software, what a spam filled adventure awaits.

I was similarly disappointed. PCWorld isn't the most authoratitive source, but this link has some leads http://www.pcworld.com/article/id,110338-page,1/article.html

Wikipedia is not a link directory. -- intgr ^#%@! 18:52, 27 May 2007 (UTC)

Which is very sad as it is one of the most reliable and reviewed sources on the entire internet...

... without being a link directory, which means it doesn't need to be one.

Still, I think this page needs to have some reference to undeletion software. Be it a list or discussion or even a link to a comparison site. I think it is quite important and the article would be incomplete without it. geitweol 10:32, 17 October 2007 (UTC) —Preceding unsigned comment added by Pnwk (talk • contribs)

Don't you think that describing software undeletion techniques without mentionning products is like describing classical music without mentionning Mozart or Beethoven? In addition, mentionning only dated tools (e.g. undelete in MSDOS, e2undel for linux while most linux systems are now using ext3) can give the impression that the article has not been updated since the last 20 years. I believe it is also questionable to mention only PhotoRec without any furter explanations in the text (PhotoRec is a carving tool - carving approaches can not recover meta information such as filenames - carving also generates a lot of false positive as it is "seeing" both deleted files and files that are not deleted). My opinion is that if there are so many undelete software available, it should not be difficult to mention at least one (one that is not dated, and one that could potentially recover meta information as well, and one that would ideally be free).203.170.144.1 (talk) 06:33, 16 December 2007 (UTC)

I believe that there are three approaches to file recovery. The first is to deal directly with the operating system and the filesystem (this is what FilesLost is doing with Windows but also ntfsprogs for NTFS, recover for ext2, Restoration for FAT and NTFS). The second approach is to scan the entire partition searching for patterns of 0 and 1 showing the beginning and the end of a file: this approach is named carving and is used by foremost, MagicRescue, PhotoRec and TestDisk). The advantage of the first approach is that it is very fast. However the first approach does not allow retrieving all the deleted files that could in theory be recovered. Carving is slower but can retrieve more files. Carving is also easier to implement because it is almost independent of the operating system. Still carving approaches have two problems. First they do not distinguish between deleted files and files that were not deleted. Second the files types to be recovered must be known in advance (otherwise the patterns of 0 and 1 to look for are unknown and a carving technique can not be applied). The third family of tools tries to mix the two approaches: the tools in this family interacts with the operating system and the file system and complement this information with carving techniques (this is what fatback and numa are doing). In addition, because operating systems and filesystems usually do not maintain the required information for successful file recovery, some have proposed to add daemon services running in the background that will gather the missing information (e2undel and giis). If you like this presentation and these references, and if you agree, I can try to update the Undeletion article (I am not a native speaker :-(). —Preceding unsigned comment added by 125.27.161.63 (talk) 15:28, 26 October 2007 (UTC)

Most the software in the list above is free software. They can be downloaded, tested and the source code can be read. They tackle the problems raised by today's filesystem for file recovery/undelete (for example in the case of ext3, in order to ensure that ext3 can safely resume an unlink after a crash, it actually zeros out the block pointers in the inode, whereas ext2 just marks these blocks as unused in the block bitmaps and marks the inode as "deleted" and leaves the block pointers alone ; this is why techniques designed for file undeletion in ext2 won't work in ext3 - you can not expect a modern (journalized in this case) file system to work in the same manner as filesystem designed in the 80's and hence it is a mistake to believe that the same undelete techniques can be applied). I believe the list above could be qualified as "verifiable" materials. Maybe they then this could be considered for inclusion in the article.203.170.144.1 (talk) 06:33, 16 December 2007 (UTC)

[edit] Undeletion on Unix

Is this statement fair?

"Undeletion was supported by MS-DOS, but is not supported by most modern UNIX file systems"

What about Testdisk and PhotoRec?

I was going to give up goggling for UNIX undelete tools after reading that statement but now am not sure that its true.

Maybe if it was said Unix operating systems are not generally bundled with Undeletetion support but tools have arisen such as Testdisk and PhotoRec?

Or is there something I am misunderstanding here?

Technically it is true; recent Unix file systems generally make no provisions for restoring removed files. File content often can be reconstructed with some magic, but it is not a feature of the file system. I remember somewhere that either the ext2 or ext3 even zeros out the inode structure on disk, making reconstruction much harder.

The original FAT file system just removed the files' blocks from the used list and even left directory entries intact, merely replacing the first letter of the filename with a "?". These ?-files would be ignored in normal directory listings, but could be used by undelete programs to recognize deleted files. -- intgr [talk] 07:51, 26 September 2007 (UTC)

I also want to ask what is "Undeletion was supported by MS-DOS"? Microsoft provides knowledge base article on how to undelete files from MS-DOS? It is supported by Microsoft?

And for ext3 undelete, this article shows even some of the most common believes are fake, even though they are explicitly told by ext3 author. 221.126.146.108 (talk) 13:04, 25 May 2008 (UTC)