remote operation or admin
peterjeremy at optushome.com.au
Fri Mar 21 01:16:07 UTC 2008
On Wed, Mar 19, 2008 at 03:10:12PM -0400, Chuck Robey wrote:
>it might be possible to find some way to extend the work domain of an smp
>system to stretch across machine lines, to jump across motherboards. Maybe
>not to be global (huge latencies scare me away), but what about just going
>3 feet, on a very high speed bus, like maybe a private pci bus? Not what
>is, what could be?
This is definitely possible. DEC built a memory channel adapter which
allowed multiple AlphaServers to share (part of) each other's RAM. You
could also try looking at Amoeba - it is a cross between a "traditional"
SMP system and a cluster. There's probably no reason why you couldn't
build a kernel module to "share" RAM between hosts using Ethernet or
similar - though it would be much slower than accessing local RAM.
>small, but with a bunch of bandwidth. So, in that case, what really are
>the differences between smp and clustering, besides the raw current size of
>the implementation? Are there huge basic differences between the
>clustering concept and by smp's actual tasks?
The access time differences between local and remote RAM mean that
there are different trade-offs: Memory coherence is extremely
expensive so more effort is expended in avoiding operations that
require coherence. In general tasks that work well in a clustered
environment have very low inter-process communication requirements.
Please excuse any delays as the result of my ISP's inability to implement
an MTA that is either RFC2821-compliant or matches their claimed behaviour.
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