HI everybody, I wonder that if this is a correct way to upgrade RHEL 4.4 to RHEL 5.3.

the main idea is:
in current RHEL 4.4 system, only install the kernel rpm (kernel-PAE-2.6.18-128.el5.i686.rpm), then modify grub menu.lst to make it to boot to RHEL 5.3.

the detailed steps are:
1. install kernel rpm
2. make initrd for RHEL 5.3
3. modify menu.lst to boot to RHEL 5.3
4. modify /etc/modprobe.conf if needed.

I have tested this and it can boot to RHEL 5.3,
but here there is a question as you may notice, that is, because only the kernel is upgrade to RHEL 5.3, but all the others like glib, system tools still remains unchanged, does this cause incompatibility problem between kernel RHEL 5.3 and RHEL 4.4 softwares(including libs)?

you do not
red hat has never supported "upgrading" between MAJOR versions

also 5.3 is VERY old the current 5 is 5.8
and the CURRENT red hat version is RHEL 6.2

contact red hat and BUY the required license ( desktop is $299/ year )
http://www.redhat.com/support/customer-portal.html

if you are NOT going to pay for it then do NOT use red hat
instead install one of the FREE rebuilds
CentOS 6.2 ( or the OLD CentOS5.8)
or
ScientificLinux 6.2 ( or the older 5.8 )


oh boy it dose

that computer should by rights not even boot

Thanks John, it is very useful. This is not about the fees. The background is that our products in the field gets some problems which we doubt caused by the disk driver or the file system driver, so we want to avoid the problem by upgrading to RHEL 5.3, while we found upgrading by the manner mentioned above takes less time than a fresh installation.

we have doubts about this kind of upgrading, but we do have enough reasons to persuade to give up this choice,

John if this is the case, are there any ways to do some tests on such a mix-matched system? Your suggestions are very appreciated!

Neither is the main thrust of his comments...

The point is that RH will NOT support such a system, nor even a full in-place upgrade across major versions http://docs.redhat.com/docs/en-US/Re..._Related_Notes.
If you need to go up to RHEL5.x, then (as above), do a fresh install of the latest ie RHEL5.8 or the other 'latest' RHEL6.2.

Yeah, Thank you two very much again, you are so nice ^_^ !