The difference between unformat and undelete

There is a nice list of data recovery types, but the difference between undelete and unformat should be explained a little further.

“Undelete” is typically used for a recovery of one file from an intact partition.

“Unformat” is typically used for a recovery of multiple files and folders off the damaged volume when none of the data is accessible any more.

The undelete software relies heavily on the fact that the filesystem is OK, except for the sought-for file. During the unformat, the data recovery software must expect to properly handle significant glitches in the volume, because even the quick format overwrites parts of the filesystem with blank data.  There are certain variations of the formatter which destroy data irreversibly, by overwriting the entire media.

The “undelete” is typically much faster than the unformat and produces significantly cleaner recovered files.