Re: C64 cluster

From: Jim Brain (
Date: 2007-11-06 22:47:52

Marko Mäkelä wrote:
> On Tue, Nov 06, 2007 at 07:00:09PM +0100, Anders Carlsson wrote:
>> Jim Brain wrote:
>>> Sellam wishes to have a cart he can plug into the machines so they do not 
>>> have to be booted by hand.  Thus, they'll be a cart there anyway.
>> How about using the tape connector? Booting the software then is just a
>> matter of pressing SHIFT + RUN/STOP.
> Or even activating SHIFT LOCK and placing some weight on the STOP key,
> so that it will start automatically.
C2N232 or some variant is fine, but sourcing that connector and having 
folks have access to something that will program an AVR may be outside 
of his scope.  But, I will send the idea forward (along with your 

> clustering protocols to the C64.  The actual parallel program would be
> distributed over the cluster network from one of the nodes.  For the
> network, I would consider using the user port, as Ruud suggested.
I will propose that idea, but something about it bothers me.  I wonder 
if you could clarify why you feel it's better to go user port than 
serial port or exp port?  When the 64 was my primary machine, I always 
cringed when I saw a new tool/toy that ran off the user port.  I felt 
that port had the least expansion options, and so you had to make hard 
choices of which thing would be plugged in.  I could not use my Jameco 
speech synthesizer with my 1650 modem, because they both needed the same 
port (user port).  At least with the expansion port, I can add an 
expander and possibly use two or more carts at the same time.

> However, given that it may be hard to source user port and cassette port
> connectors, it could be easier to build a cartridge that hosts both the
> clustering software (I'd use Flash ROM) and the interface.  I'd use a
> bus-type interface that driven by a chip that is easy to interface to
> the 6502.  Not necessarily anything from the 65xx or 68xx series, but
> perhaps something more modern.  Maybe some I2C or SPI bus, or even
> Ethernet (  However, I
> think that a solution involving the cassette port and the user port
> would be more "pure", using as much original hardware as possible
> (only one added IC, and nothing added to the CPU bus).
My thought was the cost of finding the connectors.  For a user port, you 
could rob an old modem (though I generally discourage hacking antique 
CBM items, I can make an exception for any 1660 variant).  The cassette 
port is a bit harder to find, though game carts exist in the plenty.  As 
well, a small PCB with just the card edge is a mere buck to produce and 
sell for those who want a nice looking setup.

TFE is a bit over the top for such a project, where you need to buy many 
of these units for the system as a whole.

And yes, I would bypass anything from the 65XX and 68XX series in favor 
of something with a bit easier access (though that would not be as pure, 
would it :-)

If I was going to inolve a uController, I think I would run the protocol 
over the controller, letting it act like a MAC, and then interface the 
uController to the 64 via some IO.  The uController can deal with the 
tokens, retries, and such, and the 64 just needs to dump and grab data.

But, I think using a uController for this project is also less "pure", 
as that's almost like hooking up a PC to the 64.  That's why I suggested 
the cart idea with a small flash ROM with the netboot code and a bit of 
TTL to handle the network.

So, I guess it depends on how one defines "pure"


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