🚀 go-pugleaf

	| we would like to DMA transfer data from a SGI machine to another
	| machine (DEC LSI11). Both machines are connected by Ethernet and
	| have Ethernet controllers.
	| On the LSI11 there is no room for the overhead required by TCP/IP
	| or UDP. The LSI11 initiates a DMA request (memory address, block
	| size etc.) and expects the SGI machine to listen and to respond
	| with a DMA transfer.
	
	As stated, it sounds impossible.  You could certainly write
	some simple protocol and try it out, using raw sockets on the
	SGI side (see man 7 raw), but then you still have to add
	all kinds of error checking and retry stuff if you want it at
	all reliable...
	
Thanks, Dave, for the hint. This could be a way to do it.

In fact, both machines are single user and not connected to
any net. They are, however, connected via Ethernet controllers
on both machines and the Ethernet cable. On the LSI-11 side
we are controlling the Ethernet controller directly by
accessing its registers and buffer and using its instruction
set. We are looking now for an opportunity to do the same on
the SGI machine. The 4D35 has controllers ec0 and ENP-10 (one
of each). They need not be configured for TCP/IP or other
protocols, they are available only for the low level protocol
connection to the LSI-11.

Is there a handbook available for the ec0 and ENP-10
controllers with information on registers, buffers and the
instruction set ?

By the way, the whole set-up is going to fly in a test jet
aircraft ...

Thanks for any help and best regards.

Ralf Beyer

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Ralf Beyer
German Aerospace Research Establishment (DLR), Institute for Flight
Guidance, Flughafen, D-3300 Braunschweig, Fed. Rep. of Germany
Internet: beyer@bflsgu.fl.bs.dlr.de (EARN/BITNET: fl17@dlrvmbs.bitnet) 
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