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"Jacob S. Barrett" wrote:
>
> I personally can't see needing more than about 7 tasks listening at one
> time anyway. Keep in mind that the resources on the lego are very very
> small. As far as reserving an address for IPC that would be fine. We
> could reserve 00000b for IPC and 11111b for broadcast then. It could be
> quite possible to go to 4 bits a piece but this may limit the number of
> legos too much. Although, like I said earlier, too many legos will just
> result in flooding...
>
> What does everyone think about this?
For IPC, each (unshared) connection would take 2 ports (src/dest), so 4
bits at least lets us have 7 IPCs (assuming port 0 is reserved as it is
in Berkeley sockets, 8 if it is not). I could certainly see having need
of more than 3 IPC connections. The need for IPCs may be reduced by
Markus' (I think I heard it from him) idea of making everything (even
sensors) look like any other device, using open, read, ioctl, etc.
As for limiting the number of legos, you could use a bit of the version
nybble to indicate 5/3 addressing, or you could use one of the "extra"
payload length bits for it. If one wants to have more than 14 RCXs in
one area, they could compile to use the 5/3 format. That would, of
course, render them unable to communicate with differently compiled
legos, though.
The only case that I can see for having over $2000 worth of RCXs in one
area would be some sort of group event or a very large scale project.
In either case, compiling for the other version would not be an
unmanageable restriction. And, yes, you would have problems with high
collision rates unless you forced a master/slave model.
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Message has 1 Reply:
 | | RE: LNP Repost
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| Those are some really good points, but I am still concerned about the complexity and overhead of implementing IPC on the lego. Since resources are so limited it might just be easier to use shared memory and semaphores to communicate. On the other (...) (26 years ago, 17-Apr-99, to lugnet.robotics.rcx.legos)
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Message is in Reply To:
| | Re: LNP Repost
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| I personally can't see needing more than about 7 tasks listening at one time anyway. Keep in mind that the resources on the lego are very very small. As far as reserving an address for IPC that would be fine. We could reserve 00000b for IPC and (...) (26 years ago, 17-Apr-99, to lugnet.robotics.rcx.legos)
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