some question about ext2

[Amouse]

Can anybody help me?
I study ext2 and still have some question.

- compression (file system level)
in doc said: it was developed, but "no longer actively developed/supported (as of March 2002) ".
There are any system with ext2-compressed file system?

- what about encryption in ext2?
i dont see any info about this.

- in ext2 version №1 superblock has new field: "inode_size".
but how can we calculated inode position in version №0??
we need inode size for calculating inode position.

- ext2-ext3 difference? only journaling?

[antidrugue]

- ext2-ext3 difference? only journaling?

I do think so, given that you can convert a ext2 filesystem to a ext3 one with just this command:

tune2fs -j /dev/hdaX

[DThor]

You know, I'm not sure if you can find any systems with kernel compression supported for ext2. I would imagine it was dropped simply because in addition to adding another layer of complexity, the reason for it has sort of gone away. Disks used to be very expensive, but now are cheap, especially large RAIDs, and compression slows things down, the last thing users want nowadays.

antidrugue is right - ext3 = ext2 + journalling. They are essentially identical except for that.

I'm pretty sure there is no native encryption in ext2, although of course encryption can still be accomplished. Again, I suspect the mentality behind this is to not implement stuff like this on the filesystem level. Especially something like this which changes every 5 years. I wonder what you'd do if someone created a hack that worked around it - patching existing filesystems would be fun. :/

Not sure about ext1 and inodes, sorry.

DT