Which kernels best to compile binaries against?

WoofDeF · 06-23-2005, 12:49 AM

It's so easy to load & boot up with a different kernel on Debian. However I have read that binaries should (?) really be run with the kernel verson they were compiled against. So:

1. Which kernel are the binaries in the stable repositories compiled against? 2.4.27? 2.6.8? Something earlier?

2. Will anything compiled against a 2.4.xx kernel run ok with another 2.4.yy kernel? Can I compile binaries against 2.4.27 and expect that these will run perfectly with 2.4.26? Or should it be the other way around - only compile against an older kernel for portability/forward compatibility?

EDIT: According to this it seems loadable modules may only be for specific versions or forwards-compatible vis a vis kernel versions:

Quote:

An important point to remember is that modules may be specific to a kernel version or at least a given kernel version and higher. If a module wasn't written for your kernel version you'll get an error when you try and load it

What about binaries in general?

trickykid · 06-23-2005, 05:50 PM

2.4.x series has been around longer so that would be your best bet but to me and to the naket eye, your not going to see any difference most likely from application A compiled on a 2.6.x series kernel compared to application A also compiled on a 2.4.x series kernel..

Your reference to kernel modules and drivers is totally different from binaries for applications.. etc.

rkettle · 06-23-2005, 06:00 PM

depends on how you are using it... I use 2.4 for servers because they are solid and I do not need much from them. I use 2.6 for laptops because I need usb, hibernation etc etc.

Regards
Richard

WoofDeF · 06-24-2005, 01:47 AM

Thanks for the replies - so the rule of thumb would be:

"For binaries other than driver modules it's usually not all that critical but in general it would be best to compile against 2.4.xx if you want the binary to be forwards- compatible with newer kernels."
(Obviously not talking about optimising performance here).

I take it then that binaries in both woody and sarge repositories are probably compiled against 2.4.xx.

Quote:

not going to see any difference most likely from application A compiled on a 2.6.x series kernel compared to application A also compiled on a 2.4.x series kernel.

This is something of a relief - I've been trying to custom compile a 2.4.26 kernel (from backports.org) on my new 3.1 installation in order to compile binaries that I want to run on a Knoppix-based 2.4.26 kernel system (problems so far but I'll get there?) - but if all else fails I'll just rebuild the 2.4.27 kernel that came with 3.1 and compile against that. I was hoping to get optimum performance for 2.4.26 (because it's a resource-intensive application) but if there's not going to be much or any performance difference on 2.4.26 to a binary compiled against 2.4.27 then I'm wondering if I should bother .... I'm wondering how much difference there could be between 2.4.26 and 2.4.27 ....