Kernel compatibility

Are Linux kernels backward compatible? For example, can I compile a current kernel source using SuSe 6.3 and glibc 2.1.2 and then boot 6.3 loading that kernel? If not is there any way to add ext4 support to a 2.2.14 kernel?

Thanks.

On Mon, 13 Feb 2012 03:46:03 +0000, ionmich wrote:

> Are Linux kernels backward compatible? For example, can I compile a
> current kernel source using SuSe 6.3 and glibc 2.1.2 and then boot 6.3
> loading that kernel? If not is there any way to add ext4 support to a
> 2.2.14 kernel?

There probably are no guarantees that it’d work, and it probably hasn’t
been tested as 6.3 has been out of support for years now.

Jim

Jim Henderson
openSUSE Forums Administrator
Forum Use Terms & Conditions at http://tinyurl.com/openSUSE-T-C

On 2012-02-13 04:46, ionmich wrote:
>
> Are Linux kernels backward compatible? For example, can I compile a
> current kernel source using SuSe 6.3 and glibc 2.1.2 and then boot 6.3
> loading that kernel?

I doubt it.

> If not is there any way to add ext4 support to a
> 2.2.14 kernel?

Yes: work it out to backport, or hire somebody to do it. Lots of work,
probably. Maybe you have to work at one area, then something doesn’t work
right because it expects another area to behave in certain way.

However, those old kernels are still used and probably maintained. I see
them in embedded machines.


Cheers / Saludos,

Carlos E. R.
(from 11.4 x86_64 “Celadon” at Telcontar)

On 02/13/2012 04:58 AM, Carlos E. R. wrote:
> On 2012-02-13 04:46, ionmich wrote:
>>
>> Are Linux kernels backward compatible? For example, can I compile a
>> current kernel source using SuSe 6.3 and glibc 2.1.2 and then boot 6.3
>> loading that kernel?
>
> I doubt it.
>
>> If not is there any way to add ext4 support to a
>> 2.2.14 kernel?
>
> Yes: work it out to backport, or hire somebody to do it. Lots of work,
> probably. Maybe you have to work at one area, then something doesn’t work
> right because it expects another area to behave in certain way.
>
> However, those old kernels are still used and probably maintained. I see
> them in embedded machines.

The compiler would be a serious problem. I have one system with gcc version
4.3.2 that I use to compile the kernels for a number of slow machines. The
source tree is NFS mounted and I do the installation from the ultimate host.
Some incompatibilities with later compilers are starting to show even against
the current 4.6.2. The worst case would be if the compiler generated bad code
without any warning.

Your next problem would be incompatibilities between the utilities and the
kernel. The developers take great care in trying to prevent changes in the ABI,
but 6.3 is more than 10 years old.

Backporting ext4 to 2.2 kernels would take a serious effort. Is that what is
being used? I thought that kernel 2.4 was being used by that time.

On 2012-02-13 16:46, Larry Finger wrote:

> Backporting ext4 to 2.2 kernels would take a serious effort. Is that what
> is being used? I thought that kernel 2.4 was being used by that time.

I guess 2.2

I located a CD of 6.1, but I could not see an rpm named “kernel” in the
list of archives. I located one of the floppy images; it is a gzip
compressed ext2 filesystem (!). I loopmounted it to see inside, but inside
the “/boot” directory I see:


Telcontar:~/tmp/floppy/boot # l
total 9
drwxr-xr-x  2 root root 1024 Mar 24  1999 ./
drwxr-xr-x 18 root root 1024 Mar 24  1999 ../
-rw-r--r--  1 root root 4540 Mar 24  1999 boot.b                (LILO)
-rw-r--r--  1 root root  612 Mar 24  1999 chain.b
-rw-r--r--  1 root root  620 Mar 24  1999 os2_d.b

I can not find the kernel! :-o


Cheers / Saludos,

Carlos E. R.
(from 11.4 x86_64 “Celadon” at Telcontar)