kernel designations question

[Peter Arremann]

On Sunday 04 December 2005 02:39, Tony Foster wrote:
> I am fairly new to Linux but I was fairly good with unix 10 years ago.
> I am assuming that the kernel with the SMP tag is for HW with multiple
> processors?
yes.

> If so then the question is will that SMP kernel be well behaved on a
> Single processor hardware?  I would expect it to be well behaved but
> PC hardware sometimes surprises me.
Not always. Laptops, older systems and unfortunately quite a few ultra cheap 
crappy-edition PCs (read "corporate desktops") will give you issues. 
Many of them will simply crash when booting while others show all kinds of 
random issues. ACPI implementations are still horrible these days (especially 
if you have HPQ equipment watch out) and that often shows up in weird ways. 
Slow IDE transfers, unable to detect BroadCom Xtreme gigabit network cards 
and so on are all results of running SMP kernels on hardware that doesn't 
deal with it well. The noapic kernel option helps here often. 

Also, even if it works, you're going to have some performance impact. How much 
depends on your hardware config as well as the types of programs you run. 

Usually the performance aspect doesn't really matter - but using the 
apropriate kernel for your hardware keeps you from having all kinds of weird 
problems later.

Peter.