SMP/UP kernel S01E02

[Bill Hacker]

Gergo Szakal wrote:
Well, I've been thinking of the SMP/UP issue many times, and the best
solution would be if SMP kernels could boot on UP machines. I have plenty UP
boxes and a few SMP boxes to test on. I am not claiming anyhing, this is just
'food for thought'.
Good food for thought at that!

Warp's 'merged' kernel did that - one to 16 CPU or even 64, ISTR, as did NT 3.51 
and later. Long ago.

Though I only ever had two sockets available, sometimes one CPU was pulled, so....

FreeBSD shifts gears 'automagically' as well.

Plan9 needs only to have the switch turning OFF SMP by default removed, boots 
single on UMP or SMP until so altered - the safer default, as one can at least 
get access....

NB: Some MB did ship with, for example, dual-core support, but needed a BIOS 
update to use it, and had to be booted with a uni-CPU to apply the BIOS update 
(Tyan). PITA buying or borrowing a uni-core CPU just for that purpose, and 
thankfully last year's problem.

BIOS and/or aged/transitional hardware is beyond our effective control in such 
cases, and is, or soon will be, history, given the rapid shift to multi-core.

Bill