– Introduced with kernel 1.0 in 1993
– Flexible can handle upto 4TB
– super block feature increase file system performance
– ext2 reserve 5% of disk space for root
– ext2 is popular on USB and other solid-state devices.
This is because it does not have a journaling function.
so it generally makes fewer reads and writes to the drive,
effectively extending the life of the device .
– NO journalalizm
– Provide all the feature of ext 2 + journaling and backward compatibility .
– can upgrade ext2 to ext3 without loss of data.
– journaling feature speed up the system to recover the state after power-failure
or improper mount unmount etc.
– Example: In ext2 in an improper unmount or in-between power-off etc.. so in time
of receiver it checks whole file system .
But in ext3 it keeps record of uncommitted file transactions and checks applied
on on them so system will come back up in faster and quicker .
– Introduced with kernel 2.6.28
– Ext4 is a deeper improvement over Ext3
– support larger filesystem, faster checking, nanosecond timestamps,
and verification of the journal through checksums.
– It is backward and forward compatible with versions 2 and 3, so we can
mount a ext2 or ext3 filesystem as ext4 .
– The main benefits that ext4 has over ext3 are:
– faster time-stamping
– faster file system checking
– journaling check-sums
– extents (basically automatic space allocation to avoid fragmentation)