RE: Print/price question - RE: TI-H: Why expander? Why compress? Use a F


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RE: Print/price question - RE: TI-H: Why expander? Why compress? Use a FDD!




On Tue, 20 Jan 1998, Grant Stockly wrote:

>> they can make their own chips, which can also become expensive.  Your
main
>> worry is not with hackers, but maybe the MBus, which has already shown
>> promise in its chat program.
> 
> But, MBus can only handle 1.4k per sec wiht 2 calcs, 700b with 4, I have
> proven rates of 479k per sec with a computer parallel port.  THat is with
> all ports sending and receiving.  The CalcNet bus can handle 612,000bps
> before it generates errors, and I have it regulated to 500k per sec...

Just in case someone has misunderstood...

MBus can handle 1.4k/sec with, say, 8 calcs. It could even handle 10k/sec
with 8 calcs, but the calcs themselves are too slow to handle those
speeds. The maximum speed doesn't drop as more calcs are added to the
system, it only drops when there are several simultaneous transmissions on
the bus. At any given time, the bus handles just one transmission. Several
transmissions are interlaced, so the total troughput is the same, but each
transmission is slowed down because it only gets its own share of the
total bus bandwidth.

If PC's would be connected to the MBus (I've thought about writing a
driver in C for the parallel link), higher speeds could be used. The
limiting factor is currently always the receiving calculator, TI-85's can
send at about 3kBytes/sec but receive at only about 1.3 kBytes/sec. (The
values depend on battery state and lots of other variables. Each TI is
slightly different, so I try to quote "safe" values with my experience.)

-Ozone

*** Osma Suominen *** ozone@clinet.fi *** http://www.clinet.fi/~ozone ***



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