[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: NadaNet and AppleCrate
Thank you for the verbose description. I really enjoyed the process you
described in puting togther the ideas with the hardware.
Cool, very cool.
But unfortunately, I am having more random thoughts...
It's funny, I was thinking 'just put a resistor in incrimenting sizes on
a paddle port in the apple crate and use that to assign temporary ID
numbers".
I was also thinking about your 'hands-off' approach to booting. Since
you are only wanting to throw one switch at power up, why not change the
reset length of each board using the same (add a resistor) technique to
cause each board to hold it's power-on reset signal a little longer.
(This can be done using a card in a slot if necessary to hold the reset
line low on power-up. Each A2 would still cascade boot and get the next
available ID number, per my previous thoughts.
Something I didn't quite realize is that you are buring custom ROMS to
do the NADA net so one could theoretically just 'hard code' an ID number
and then not have to worry about temp and permanent IDs. If a
hardware failure occurs, pull the rom and drop it onto another board and
insert it back in the rack. The only time a reassignment would need to
occur is if the message server went missing from the network. You'd
still need to keep track of operation ID numbers so one could assign
tasks, but ID arbitration would be a lot less necessary on boot.
So now that I understand where you are coming from, and what you hope to
accomplish; IE, a network of JUST wires and software with no additional
hardware... what would happen if you tied the game port to the
interrupt signal on the slot of the next board? Not necessarily true
fault tolerent parallel processing, more like cascade assignment and
processing. Since each board would be under the control of the next
board up. Of course if you go this far, why not wire the slots together
(Pick a slot) and move and entire byte at a time using the slot latch...
:)
Michael J. Mahon wrote:
Today I added considerably more description to the NadaNet page
for those of you who are interested.