Difference between EXT2, EXT3,EXT4

Features	EXT2 Second extended file system	EXT3 Third extended filesystem	EXT4 Fourth extended file system
Developer(s)	Rémy Card	Stephen Tweedie	Mingming Cao, Andreas Dilger, Alex Zhuravlev, others
File allocation	bitmap (free space), table (metadata)	bitmap (free space), table (metadata)	Extents/Bitmap
Max. volume size	2–32 TiB	4 TiB – 32 TiB	1 EiB
Max. file size	16 GiB – 2 TiB	16 GiB – 2 TiB	16 TiB (for 4k block filesystem)
Max. number of files	1018	Variable, allocated at creation time	4 billion (specified at filesystem creation time)
Max. file name length	255 bytes	255 bytes	255 bytes
Allowed characters in file names	All bytes except NUL ('\0') and '/'	All bytes except NUL ('\0') and '/'	All bytes except NUL ('\0') and '/' and the special file names "." and ".."
Date range	December 14, 1901 - January 18, 2038	December 14, 1901 – January 18, 2038	14 December 1901 - 25 April 2514
Supported operating systems	Linux, BSD, Windows (through an IFS), Mac OS X	Linux, BSD, Windows (through an IFS)	Linux FreeBSD (read-only with ext4fuse) Mac OS X (read-only with ext4fuse, full with ExtFS) Windows (Read/Write without journaling with ext2fsd)