27 Feb
2002
27 Feb
'02
6:22 a.m.
On 2002.02.27 19:05 Chuck McManis wrote:
In my experience with the SII chip you set up a buffer
in its shared
memory
with the MSCP "packet" layed out, and the node number of where you
wanted
it to go at the front. Then you write the that address into the
descriptor
register and the SII chip picks it up and drops it off at the drive.
This would
mean that the SII implements at least a part of SCA in
hardware. Hmmm.
Questions that were unanswered in my mind when I put
this down about
this time last year were:
1) maintaining the physical/virtual mapping between the 128KB
buffer and main memory.
This seams to be one of the main features of
the SHAC chip. It is a
"nexus" device. This means it does all that nifty scatter-gather DMA
stuff and the like on its own. At least this is my understanding that I
got for the term "nexus" device. (Someone may give me more enlightening
about this.)
--
tsch??,
Jochen
Homepage: http://www.unixag-kl.fh-kl.de/~jkunz/