Beowulf: A theorical approach

[Greg Lindahl]

> It provided cache coherent remote user space access (including remote
> DMA) with control from user processes in Solaris without requiring a
> kernel trap. But _not_ an SMP model, although you had complete remote
> store access, you had to _know_ that you wanted to access remote
> store.

Today, this is called the "SALC" programming model: shared address, local
consistancy. You explicitly fetch data to your local address space, and you
are responsible for making sure it's up to date.

> The reasons no-one does it any more are

That would be a surprise for those of us who are planning on doing it. The
UPC++ and CoArray Fortran languages use SALC, and I expect to have SALC
hardware when PCI-X gets here. MPI-2's one-sided communications can be sped
up if you have SALC hardware.

-- greg