[saikee]

Here is an example, using a Debian 4R0 with a 2.6.18 kernel to mount Ubuntu 9.04 in sda6 formatted to Ext4 filing system

debian:/home/saikee# mkdir /mnt/sda6
mkdir: cannot create directory `/mnt/sda6': File exists
debian:/home/saikee# mount /dev/sda6 /mnt/sda6
mount: wrong fs type, bad option, bad superblock on /dev/sda6,
       missing codepage or other error
       In some cases useful info is found in syslog - try
       dmesg | tail  or so

debian:/home/saikee# mount -t ext4 /dev/sda6 /mnt/sda6
mount: unknown filesystem type 'ext4'
debian:/home/saikee# mount -t ext3 /dev/sda6 /mnt/sda6
mount: wrong fs type, bad option, bad superblock on /dev/sda6,
       missing codepage or other error
       In some cases useful info is found in syslog - try
       dmesg | tail  or so


debian:/home/saikee# uname -a
Linux debian 2.6.18-6-686 #1 SMP Sat May 24 10:24:42 UTC 2008 i686 GNU/Linux

I tried it with DSL which failed too and its kernel is 2.4.31, one of the oldest around.

Here is anther attempt to mount it by Mepis

root@mepis1:/home/saikee# mkdir /mnt/sda6
mkdir: cannot create directory `/mnt/sda6': File exists
root@mepis1:/home/saikee# mount /dev/sda6 /mnt/sda6
mount: unknown filesystem type 'ext4'
root@mepis1:/home/saikee# uname -a
Linux mepis1 2.6.27-1-mepis64-smp #1 SMP PREEMPT Wed Feb 18 10:19:55 EST 2009 x86_64 GNU/Linux
root@mepis1:/home/saikee#

The above clearly suggests a Linux with 2.6.27-1 kernel is able to see an Ext4 partition but unable to mount it.

Here is the attempt by Mandriva, with a 2.6.28 kernel

[root@localhost saikee]# mount /dev/sda6 /mnt/sda6
[root@localhost saikee]# ls /mnt/sda6
abit/  boot/   dev/  home/        lib/         media/  opt/   root/  selinux/  sys/  usr/  vmlinuz@
bin/   cdrom@  etc/  initrd.img@  lost+found/  mnt/    proc/  sbin/  srv/      tmp/  var/
[root@localhost saikee]# uname -a
Linux localhost 2.6.28.4-desktop-1mnb #1 SMP Mon Feb 9 07:18:26 EST 2009 x86_64 Intel(R) Core(TM)2 CPU    6700  @ 2.66GHz GNU/Linux
[root@localhost saikee]#

Thus only the Mandriva with the latest 2.6.28 kernel succeeded in mounting the sda6 partition formatted in Ext4.

The Ext4 has been around for a while but only declared "stable" in the 2.6.28 kernel.

In conclusion one needs a newish kernel to read an Ext4 partition.

[Elvandil]

Thank you, saikee. I would have bet important money that you would clarify this for us once you saw the thread.

We all appreciate your input.

[saikee]

Elvandil,

Examples speak better words. It pays to be cautious.

[RootbeaR]

Yes, thanks saikee.

I must say I am disappointed.

I assumed there would be a driver available much like ntfs-3g for MS.


Here it was under my nose:
"Ext4 Filesystem Explained in Plain English"
http://hehe2.net/linux-general/ext4-...plain-english/

[Elvandil]

It won't be long before all new OS's have support for Ext4, so it's really a trivial problem. The only people who might worry are those that are running old OS's and don't want to update.

[Elvandil]

Originally Posted by saikee

Elvandil,

Examples speak better words. It pays to be cautious.

Absolutely right. I almost never recommend a program to anyone that I havn't tried myself, and would have tested the possibilities with Ext4 if I had had the resources to do so. Thank you again.

I wouldn't have stuck my nose in here at all if it weren't for the fact that, different as one OS may be from another, they share some fundamental principles. Just as one model of automobile is not built according to different laws of physics, the family of OS's is more similar to one another than different.

[saikee]

Originally Posted by RootbeaR

Yes, thanks saikee.

I must say I am disappointed.

I assumed there would be a driver available much like ntfs-3g for MS.


Here it was under my nose:
"Ext4 Filesystem Explained in Plain English"
http://hehe2.net/linux-general/ext4-...plain-english/

I think there must be but I haven't bothered with it.

Too many things are getting interesting. I managed to get 130 partitions out of one hard disk from the 2.6.28 kernel but the majority of Linux are not ready to use them yet including their partitioning tools and installers.

[RootbeaR]

Originally Posted by saikee

Too many things are getting interesting.

Yes, I am finding that a problem.

I feel like I need to take a break from updating until they slow down a little.

So much reading, so little time.