[Leaplist] Install Question -- march/mopt and i486/i686

[Bryan J. Smith]

Stephen A. Cullum wrote:  
> These are different kernel images. They were compiled for
> different types of computers and cpu.

The i486 should run on anything.  It's been an extremely long time
since anything required i386.  I think the first NexGen Nx586 has a
few i486 instructions missing and variations in its TLB, but anything
"i386" is actually the full i486 with TLB these days.

The i686 (Pentium Pro) should run on anything sold today sans some
SGS Thompson embedded x86 designs, old, pre-M2 Cyrix or a few, other,
embedded cores that are far less known or deployed.  Some "i686"
kernels are actually "-march i486" with "-mopt i686" so they will run
on i486, but run much better on i686.  The i686 target in 2.6 also
does dynamic loading of optimizations -- i.e., no need to build a
separate Athlon target any more.

_Never_ run i586 _except_ on a true, original Intel Pentium (P54 or
P55), not a Pentium Pro, II or later.  Intel i586 targets have many
"hacks" in its optimization that hurt performance on most other CPUs
(although Athlon cores can usually handle them better than most, long
story, but you'd rather run i686 on them).

Targeting i686 has so many advantages, it's done by default in most
distros now.

> I think that the 686 is for a notebook type computer and if is
> doesn't have smp option it is for a single core.

The single v. multi core scheduling is getting more and more blurry
in the 2.6 tree.  For x86-64, there's virtually no difference.  With
the new, single, unified x86 target (merger of i386 and x86-64
trees), I'm surprised if it's still built.


-- 
Bryan J. Smith       Professional, Technical Annoyance
b.j.smith at ieee.org  http://www.linkedin.com/in/bjsmith
------------------------------------------------------
       Fission Power:  An Inconvenient Solution