Re: FYI: I2O Architecture (fwd)

Michael Neuffer (neuffer@nomis.i-connect.net)
Tue, 19 Nov 1996 10:19:41 -0800 (PST)

On Tue, 19 Nov 1996, Robert Glamm wrote:
> Looks horribly inefficient to me (as opposed to what they claim). I am
> unconvinced that a "message-passing interface" to device driver/OS
> interaction can provide "high-performance I/O systems." Why stick
> what essentially amounts to another protocol stack sandwiched between
> the hardware-specific points and the O/S layer? Eesh.

What do you think is SCSI ? SCSI is exactly such a protocol.

> The only slightly cool thing that could arise out of this would be a
> truly heterogeneous multiprocessor; with a little extension, one machine
> could call OS services on another machine via the protocol layer. This
> might be desirable for distributed-memory systems except for the fact that one
> bad kernel call could bring down all the machines in the cluster.

You can buy those cards already. Get a DPT SCSI controller and you have
your "truly heterogeneous multiprocessor" machine.
A DPT contoller is a SCSI IO coprocessor that communicates via a protcol
with its host and does large chunks of necessary processing autonomously.
Services like RAID are not visible to the host and thus takes the load
of providing such services from the host CPU.

You can even attach a serial terminal to it.....

Mike

Michael Neuffer i-Connect.Net, a Division of iConnect Corp.
mike@i-Connect.Net 14355 SW Allen Blvd., Suite 140
503.641.8774 Beaverton, OR 97005