why can't we use old initrd image file?

[rakeshkumar]

i have installed fedora 12 and kernel version is 2.6.31.XXx and also download a kernel 2.6.30 and made some changes wiht make menuconfig
then make
and make install. this creates a vmlinuz file in /boot but no initrd file file will be created . so i manually edited menu.lst file and added new entry with my new vmlinz and initrd of currently running kernel i.e old initrd file.

this gives a kernel panic message.. what is wrong with this?

[hazel]

Your initrd image must match your kernel. To make a new one, you can use the mkinitrd command.

[gunalanr]

Hai rakesh,

initrd image is nothing but a set of module image to be present in the memory during boot time. so that if anything goes wrong in kernel diagloue or initrd image file, you might get kernel panic error. i hope that you might ge the following error:

error 15: file not found.
For this kind of errors, you suppose to rebuild the initrd image as hazel said.

Please kept it this the initrd version and the kernel version should similar. each kernel should have its appropriate initrd image.
I hope that you may get clear idea.

reply back if you need more info, and valuable suggestion from other members are also welcome.
Thanking you