difference between ext2 and ext3 in linux

Ext3 is a tiny bit slower than ext2 is, but it holds tremendous advantages.
There is really only one difference between ext2 and ext3, and that is that ext3 uses a journal to prevent filesystem corruption in the case of an unclean shutdown (ie. before the filesystem is synced to disk). That makes ext3 a bit slower than ext2 since all metadata changes are written to the journal, and then flushed to disk, but on the other hand you don't risk having the entire filesystem destroyed at power failure or if an unwitted person turns the computer off uncleanly. You don't have to check the filesystem after an unclean shutdown either.
Ext3 has three levels of journalling. Metadata (ie. internal filesystem structures) are always journalled, so that the filesystem itself is never corrupted. How ordinary data is written to the file system is controllable, though. The default option is the "ordered" mode, which causes file contents to be written to the filesystem before metadata is even committed to the journal. The highest reliable mode is called the "journal" mode, which causes file data to be committed to the journal before it is flushed to its final place, like the metadata. The least reliable mode, but rumoured to be the fastest, is called the "writeback" mode, which makes no promises at all regarding the consistency of file data. Only metadata is output reliably in writeback mode.

So as for anything else, it's mainly a matter of priority. If you don't want ultimate speed, go with ext3. If you need the highest speed that is theoratically aquirable though, then go with ext2. For that to be effective you'll probably need a really advanced hard drive controller, though.

The major difference is 1.

I disagree: it is 42

To ibm0021
I am surprised by your boldness. Feed this question into google, not into a forum of people dedicating their time to help others.

jlinkels

42 is the answer to the Ultimate Question of Life, The Universe, and Everything.

Ext2, ext3 and Linux are all part of the Universe. Hence, the difference between etx2 and ext3, intersected with Linux is also part of the Universe. As they are all part of the universe, and 42 is the answer to the Ultimate Question of Life, The Universe, and Everything, 42 qualifies as a valid answer for everything which is part of the Universe.

Basically you answered the question: "What was the question for which 42 is the answer?"
I have read my classics

jlinkels

Indeed...

ok thanks........................

Thanks

I'll defend your right to disagree.......

*ahem*homeworkassignment*ahem* ?

Some link to be searched: https://ext4.wiki.kernel.org/index.php/Main_Page .