> SGI Origin/Onyx 3000 machines are built from "bricks." There are
> several types of bricks that make up a system.
this is one of the coolest things I've seen... it's a very modular
architecture; so you just build exactly the computer you need, and when you
want to expand it, you just add more pieces to it. instead of a fixed, rigid
backplane, they use NUMAlink (formerly called CrayLink) cables to go from
brick to brick. makes installation very flexible.
> I I/O Brick, includes two drives, CD and XIO. Required to boot a
> system.
> C CPU brick, includes 4 MIPS CPUs, memory, NumaLink and XIO
> P PCI brick, include (I think) 6 PCI buses with 2 slots each
> D Disk brick, 12 drive JBOD (Just a Bunch of Disks)
> R Router, connects four C-bricks together
> X Metarouter, connects R bricks together.
> G Graphics brick, makes the system an Onyx
as I understand it; the C-brick has a NUMALink connector, and a XTown
('crosstown') connector on it. the NUMALink goes to the router brick; and
the XTown goes to the I/O brick. If you add a graphics brick; I understand
that it connects to the I-brick, and from there to the C-brick.
but how do you get decent bandwidth from the CPUs to the graphics unit,
using such a long chain (with possibly 6 feet of cable between each brick)?
Obviously the graphics unit has some pretty impressive onboard GPUs, and a
sizeable cache of its own; but it seems strange to go through an
intermediate unit on the way to main memory.
or maybe I'm just misreading the product literature.
Carl Soderstrom.
--
Network Engineer
Real-Time Enterprises
(952) 943-8700