ia64 (looks complicated ...)Well as far as I can tell it was not even used 12 or so years ago on Itanium when I worked on that stuff.
My notes tell that on UP ia64 (RX2620), !NUMA was broken with both SPARSEMEM and DISCONTIGMEM. NUMA+SPARSEMEM or !NUMA worked. Even NUMA+DISCONTIGMEM worked, that was my config on 2-CPU RX2660. -- Meelis Roos