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Sadly I didn't get to play with EcoNet even though our school had a computer room full of BBC B micros (and one 380Z). Having been deprived, I am wondering how

Sadly I didn't get to play with EcoNet even though our school had a computer room full of BBC B micros (and one 380Z). Having been deprived, I am wondering how Econet actually was supposed to be wired up. Was it like early thin net ethernet with DIN instead of BNC cabling? Or was it 'hub and spoke'? I can't imagine there were ethernet style routers/hubs for EcoNet but the teachers were supposed to have some type of god-like power over pupils' machines so I would like to know how that was supposed to work too.

david-given 10y ago
The bus itself was two twisted pairs, one for clock and one for data (he says after looking it up), mediated by a MC68B54 data controller. Computers appear to have been patched in in parallel. Each segment had to have a terminator at each end plus a powered clock driver, which meant that setting up ad-hoc Econet links was basically too hard. The speed of the clock determined the transfer rate of the network. There were routers, which would bridge between multiple networks --- they connected to multiple Econet segments and just relayed packets addressed to the other network. Apparently their primary purpose was to speed-match between BBC Micro networks, which had to be quite slow, and Archimedes networks, which could be much faster. The hardware's painfully antiquated by modern standards, of course; I2C is faster and cheaper and doesn't need clocks or terminators or any of that nonsense. Also, from flipping through the Advanced User Guide, it looks like it's entirely packet based, but it does a four-way handshake for every packet --- effectively setting up a connection and tearing it down again! Which gives you reliable delivery but at a huge cost. We forget just how good TCP/IP is. I suspect the god-like power mentioned was simply having a copy of the Advanced Users Guide and knowing about * VIEW and * REMOTE. Also apparently there was an Econet interface available for the 380Z, so your school was totally missing out there.

david-given 10y ago

The bus itself was two twisted pairs, one for clock and one for data (he says after looking it up), mediated by a MC68B54 data controller. Computers appear to have been patched in in parallel. Each segment had to have a terminator at each end plus a powered clock driver, which meant that setting up ad-hoc Econet links was basically too hard. The speed of the clock determined the transfer rate of the network. There were routers, which would bridge between multiple networks --- they connected to multiple Econet segments and just relayed packets addressed to the other network. Apparently their primary purpose was to speed-match between BBC Micro networks, which had to be quite slow, and Archimedes networks, which could be much faster. The hardware's painfully antiquated by modern standards, of course; I2C is faster and cheaper and doesn't need clocks or terminators or any of that nonsense. Also, from flipping through the Advanced User Guide, it looks like it's entirely packet based, but it does a four-way handshake for every packet --- effectively setting up a connection and tearing it down again! Which gives you reliable delivery but at a huge cost. We forget just how good TCP/IP is. I suspect the god-like power mentioned was simply having a copy of the Advanced Users Guide and knowing about * VIEW and * REMOTE. Also apparently there was an Econet interface available for the 380Z, so your school was totally missing out there.