Alto Ether

Juergen Buchmueller pullmoll at
Sat Jul 14 15:36:22 PDT 2007

Are the PROMs from an Ethernet board available somewhere? There's at least
one that would help me: a49. It is similiar to the display a38, since it's
controlling the FIFO on the Ethernet board.

I constructed the (probable) contents for now, but it'd be of course better
to have the real thing.

There are also two more PROMs, but you won't need them unless you're going
to turn some PC I/O port into an Alto Ether transceiver. They are the Phase
Encoder 1 & 2 parts a41 and a42.

What I'm thinking about is how to connect (virtual) Altos over IPv4. I have
little experience with UDP and am undecided whether it'd make more sense to
have some kind of Alto Ether TCP-IPv4 server. This server would just pool
every client's incoming packet and send (broadcast?) the pooled data to
everyone who's connected on a regular basis, or perhaps after every
incoming packet. Do you, Eric, or anyone reading here have other ideas or
experience how to tackle this?

The most interesting question: how could real Altos take part in any such
scenario? Build some Alto Ethernet to TCP over IPv4 gateway hardware? Or
perhaps sample the Alto Ether on a PC or Mac and also drive it after
receiving a packet from some Alto Ether TCP server?

I think this requires some brainstorming...

Meanwhile I got Salto reading the (internally only) broadcasted duckbreath
packet on a boot with the backspace key held down. Of course noone's there
to answer any questions for a boot file transfer...

Pushing packets to a (not yet existing) transceiver after a disk boot
also seems to work. The system sends three packets with very short delays,
then waits for a short while and again sends three packets with 015 words

packet 1:
000023 001000 000026 000206 000566 000000 000000 000000
000004 000023 000000 000273 177777 crc:142764

packet 2:
000023 001000 000026 000206 000622 000000 000000 000000
000004 000023 000000 000311 177777 crc:112120

packet 3:
000023 001000 000026 000206 000656 000000 000000 000000
000004 000023 000000 000327 177777 crc:147622

... etc.

The machine's Ethernet ID is 023, and the packets are obviously broadcasts
of type 001000.. whatever that is.

I think the first thing to try is to connect the packet level to some unix
domain socket and connect 2 Salto instances.


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