[Beowulf] DIMMnet-1 DIMM slot NIC?

[Joachim Worringen]

Mark Hahn wrote:
>>>What is your reasoning?  Bandwidth limitations?  Address bits?  Latency?
>>
>>As I wrote, not enough address space. A single DIMM can cover at most 
> 
> 
> this is slightly overbroad, since no one said that the net-dimm has to 
> implement a flat addressing scheme.  that is, that the only addressing bits
> come from the normal row/col addresses used in the standard dram protocol.
> 
> suppose, for instance, row/col merely selected the destination node, and the 
> first 64 bits of the data burst defined the memory address (in the destination
> node's address space).

Interesting idea, but then you loose the transparent operation mode. But 
generally, this approach looks more like a hack to me. I.e., alhtough 
this address space would look like standard RAM to the hardware and OS, 
you'd need to avoid that it is used as such. You will probably encounter 
having problems with this approach when the BIOS runs on bootup...

  Joachim

-- 
Joachim Worringen - NEC C&C research lab St.Augustin
fon +49-2241-9252.20 - fax .99 - http://www.ccrl-nece.de