Re: LZ: Ti-H:RF Link for chatting.
[Prev][Next][Index][Thread]
Re: LZ: Ti-H:RF Link for chatting.
On Wed, 6 Nov 1996, Jason C. Wenger wrote:
> >Or you could use a token ring idea, but that may be too slow...
>
> Don't you need a server for that?
Nope. Just that the netsoftware understands TOKENS. If thou dost not
posess the Holy and Sacred TOKEN, thou shalt remain silent and forever
hold thy peace. So a message looks like this:
[a b c d e {f,f,f,...,f} gg]
a = number of calcs
b = calc number on net
c = destination
d = who gets the token next
e = number of data bytes !(c>256)
f = data
g = checksum <-- that "gg" is not a literal. 'Tis computed for every packet
I guess d could be 1+mod(x,256) ...but that limits you to 256 calcs. just
pass the TOKE_n around ;) In a Token Ring network topology there is no
_Central_ server.... maybe one gateway or router, but it's not like a Star
LAN. d can be specified so one calc can talk to another calc. You could
rig up all kinds of cute net apps that way. We really ought to clone a
commercial protocol. Make it compatible with the rest of the world. I
can see it now... <dream_sequence> Us... sitting in a 4th year computer
science course... doing massively parallel computation research programmed
in FORTRAN....all on a TI-85. </dream_sequence>
> Remember Thoreau-- Simplify. Just limit yourself to 2 calculator
> linking.
James Ockham -- Ockham -> Occam -> O'Cam -> Ocam
Invented Occam's Razor: When there exist several solutions, choose the
simplest one. There's a supercomputer parallel programming language named
after him, BTW. Which brings us right back on topic.
Networked processors. CS/MCAD. Collision Sense/Multiple Carrier Access
Detect. Cute feature of the ANSI 802.* transport layers. (TokenRing,
Ethernet, TCP/IP) Can sense when multiple packets arrive (almost)
simultaneously and causes retransmission and it also knows when other
hardware is accessing the physical link. So.. let's all look up ethernet
protocols and Token Ring protocol... just for inspiration... to see how
it's done commercially. 100base-T for the TI-85 <-- pipe dream
But it should be possible. Build a bunch of boxes connected w/ UT2P and
plug in your link cables. White wire for data(bidirectional) and red for
CS/MCAD. This could work, because only one calc will be transmitting. We
listen for other hardware asserting BUSY on white, and then read the first
5 bytes, and go into a spin routine, unless we're being addressed. If any
of this made no sense, ask, and I will try put together some pseudocode to
make this go.
<pre>
--
Chris Kuethe <ckuethe@gpu.srv.ualberta.ca> LPGV Electronics and Controls
RSA in 3 lines of PERL:
#!/bin/perl -sp0777i<X+d*lMLa^*lN%0]dsXx++lMlN/dsM0<j]dsj
$/=unpack('H*',$_);$_=`echo 16dio\U$k"SK$/SM$n\EsN0p[lN*1
lK[d2%Sa2/d0$^Ixp"|dc`;s/\W//g;$_=pack('H*',/((..)*)$/)
</pre>
References: