On 8/1/23 7:20 PM, David Crayford wrote:
What’s the difference between between channelized I/O and a rack
of x86 servers connected to a SAN using fibre channel driven by high
speed HBAs?
I don't know.
My understanding is that Fibre Channel is an evolution of SCSI which is
supposedly a somewhat intelligent controller wherein the OS asks said
controller to fetch / store some data for it. As I understand it, the
OS & main CPU aren't involved in the transfer beyond asking the
controller to do the transfer on it's behalf.
I'd have to reference documentation to see if / how much Direct Memory
Access comes into play vs the CPU's involvement in the transfer to /
from the controller.
But between the controller and the back end drive, as I understand it,
the CPU ins't involved.
So I can't say that "a rack of x86 servers connected to a SAN using
fibre channel" isn't using channelized I/O. I think in many ways they are.
This is a place where minutia matters.
Grnat. . . .
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