Recover formatted ext3 partition

Both ext3 and ext4 are journaling filesystems, in addition this list several differences, the most relevant are:

• Maximum individual file size can be from 16 GB to 16 TB
• Overall maximum ext4 file system size is 1 EB (exabyte). 1 EB = 1024 PB (petabyte). 1 PB = 1024 TB (terabyte).
• Directory can contain a maximum of 64,000 subdirectories (as opposed to 32,000 in ext3)
• Several other new features are introduced in ext4: multiblock allocation, delayed allocation, journal checksum. fast fsck, etc. All you need to know is that these new features have improved the performance and reliability of the filesystem when compared to ext3.

The interesting thing for you might be the faster fsck, the others are probably of less significance in this particular situation (unless your disk gets a growth spurt and magically can contain much larger files).

If you are not going to use that partition intensively I would not recommend converting (at least not without a backup).

The forensic tools the recovery company will use could include EnCase Forensic, which is probably the leading forensic data recovery utility. EnCase takes the drive image recovers the raw data, then makes pretty intelligent assumptions as to what blocks form what files.

There are still limitations, so an element of this is likely to be manually processed.

On a Windows machine you'd likely have a copy of your Master File Table. Sadly, under ext4 this doesn't exist, but you can make reasonable assumptions based on inode timestamps and other metadata.