Since you are interested in the matter, the 2.2 TB is not really-really the limit of LBA in the MBR, the actual limit is actually almost double that, if you can accept to have 1 primary partition (or max 3 or 2 primaries max + logical volumes inside extended) within the 2.2 TB limit and a single primary partition starting a few sectors before the limit and extending up to another 2.2 TB [1] (and this would cover both 3 and 4 TB disks, which are still very common).

If you prefer, 2.2 TB is the MBR limit for a single partition on disk.

[1] there may be other limitations, i.e. in MS operating systems the above works just fine in Windows 7 (and most probably later MS operating systems) but it doesn't work in XP