Re: "Co-Processor" Apple ?

["Robert C." <robc638killspam@sympatico.ca>]

"Michael J. Mahon" <mjmahon@aol.com> wrote in message
20040820033332.26080.00002250@mb-m28.aol.com">news:20040820033332.26080.00002250@mb-m28.aol.com...
> Robert C. replied:
>
> >"Michael J. Mahon" <mjmahon@aol.com> wrote in message
> >20040817220555.19157.00003638@mb-m06.aol.com">news:20040817220555.19157.00003638@mb-m06.aol.com...
> >> Robert C. replied:
> >>
> >> >"Michael J. Mahon" <mjmahon@aol.com> wrote in message
> >> >
> >> >> All these issues caused me to prefer using an annunciator output
> >> >> and a pushbutton input for NadaNet--it is both simpler and more
> >> >> capable.
> >> >
> >> >The more I read about NadaNet, the more I think it is "the next best
> >thing"
> >> >to true Ethernet.
> >>
> >> I'm glad you like what you've read.  ;-)
> >>
> >> The practical bandwidth is about 8 kilobytes/sec, which is a lot
> >> lower than the peak bandwidth of Ethernet, but the latency is
> >> very low and Apple II's don't need screaming bandwidth.
> >>
> >> NadaNet delivers data at about the same rate as a 5.25" disk,
> >> which is quite practical for many purposes.
> >>
> >> And you can't beat the price...  ;-)
> >>
> >> I've just written a Applesoft program "prun" which will do a
> >> "parallel run" of any Applesoft program on all networked
> >> machines running the service loop.  The slaves complete
> >> their computation and return to the service loop by doing
> >> any input operation.
> >>
> >> I've been pretty busy reorganizing my lab area for the last
> >> few weeks, and expect that to go on for another few weeks,
> >> but my next NadaNet project is assembling the code to
> >> run at the top of RAM (at $B800 for AppleCrate slaves),
> >> so that HIMEM: can easily protect it, and all of low memory
> >> will be contiguous for program(s).
> >>
> >> I'll give some thought to self-relocation in the process...
> >
> >I have downloaded and read the documentation and code and am in the
process
> >of entering the code one byte at at time. I know the files are available
for
> >download too, but I figured: what better way to learn the code than to
enter
> >it manually.
>
> Entering the code in the monitor is certainly an excercise in
> patience!  At least you can "List" the code to verify that it is
> correct.  (Errors in hand entry are a major issue.)
>
> > I will be using my 2 Apples as a "Master" / "Slave" setup, so I
> >was wondering, is there any parts of the code that should be changed? The
> >Applesoft program you wrote can be easily changed so that it does not use
> >"machine 2" as a message center, and the Slave polls the Master upon
> >completion of its job.
>
> Yes, it can be changed, but as written it requires at least three
> machines:  the master, the message server, and at least one
> "worker" slave.  The master initializes the system and puts
> "jobs" in a message queue, "workers" receive jobs from the
> message queue and place results in another message queue,
> and the master receives the results and prints them.
>
> As I note in the documentation, the primary function of the message
> server is to permit queued asynchronous communication between
> machines.  If you don't use a message server, then any two
> communicating machines must "rendezvous", usually by one
> of them polling in its service loop.
>
> If you are only connecting two machines, then you may want to try
> some different things.  The "parallel run" program would allow you
> to initiate an arbitrary Applesoft program on the slave machine from
> the master.  I'll look at putting it up on the web in the next few days.
> (Although you can probably write your own using "PARALLEL.SIM"
> as a template.)
>
> You will not need the NadaBoot code, since you will not be
> running a "diskless" slave.  That also helps with debugging,
> since you will be able to debug your slave machine(s) locally.
> (Some network debug capability is getting higher on my want
> list.  ;-)
>
> (As I've been cleaning and reorganizing my lab, I discovered
> that it has a _floor_!!  Amazing!  ;-)
>
> -michael
>
> Check out parallel computing for 8-bit Apples on my
> Home page:  http://members.aol.com/MJMahon/


I still do not quite understand the "machine 2 as the message server" part
of NadaNet: Is it the Applesoft part that dictates that Machine 2 will be
used as a message server, or is it NadaNet itself that requires this?

~Robert~