networked C64's?
Charles Houck
Connect two or more 1541 (or 1571 or 1581) disk drives via serial cables
with a C64 at each end. Seems each C64 would have access to each of the
1541"s in the serial chain.
Probably no practical application for this, just an experiment I considered
trying.
Matthew Montchalin
Be sure to modify the serial cables so that the RES line doesn't go all
the way through to the other C-64.
John Iannetta
"Can someone tell me if this would work, or would it fry one or both C64's?
Connect two or more 1541 (or 1571 or 1581) disk drives via serial cables
with a C64 at each end. Seems each C64 would have access to each of the
1541"s in the serial chain.".
The C-64 and 15XX drives use open-collector devices at the IEC (serial)
ports, so you won't hurt any equipment by playing around with that
configuration. You should be able to access the drives from either computer,
as long as you do a:
poke56576,7
on the other computer.
--
123 456
789 *0#
If you see a telephone keypad above, you're probably using a Commodore 64.
Jim
cables interconnecting.
Things work fine EXCEPT if one of the 64's tries to access the 1541 while the
OTHER 64 is using it... causes immediate lockups. So long as they work
"one-at-a-time", it works fine.
Jim
Niall Tracey
: I've used 2 C64's sharing one 1541 disk drive before, just with stock serial
: cables interconnecting.
: Things work fine EXCEPT if one of the 64's tries to access the 1541 while the
: OTHER 64 is using it... causes immediate lockups. So long as they work
: "one-at-a-time", it works fine.
The missing item - mutual exclusion: IE one computer should be locked by
the other. A side question: is there any signal inside the C64 that
signals use of the serial port? If so, C64s could be rigged to stop each
other dead by disabling the chip-enable on the processors and work away
happily. Another possible hack for my potential megaly-hacked C64 (must
get started on that soon...).
: John Iannetta wrote:
: > "Charles Houck" <the...@netins.net> said:
: >
: > "Can someone tell me if this would work, or would it fry one or both C64's?
: > Connect two or more 1541 (or 1571 or 1581) disk drives via serial cables
: > with a C64 at each end. Seems each C64 would have access to each of the
: > 1541"s in the serial chain.".
: >
: > The C-64 and 15XX drives use open-collector devices at the IEC (serial)
: > ports, so you won't hurt any equipment by playing around with that
: > configuration. You should be able to access the drives from either computer,
: > as long as you do a:
: >
: > poke56576,7
: >
: > on the other computer.
: > --
: > 123 456
: > 789 *0#
: >
: > If you see a telephone keypad above, you're probably using a Commodore 64.
--
NT As long as but a hundred of us remain alive, never will we on any
\ \/ /conditions be brought under English rule. It is in truth not for
\ / glory, nor riches, nor honours that we are fighting, but for
/ \ freedom -- for that alone, which no honest man gives up but with
/ /\ \life itself. -- Arbroath, 1320
John Iannetta
"The missing item - mutual exclusion: IE one computer should be locked by
the other. A side question: is there any signal inside the C64 that
signals use of the serial port? If so, C64s could be rigged to stop each
other dead by disabling the chip-enable on the processors and work away
happily. Another possible hack for my potential megaly-hacked C64 (must
get started on that soon...).".
If you have two C-64's connected to one or more IEC (serial) devices, and
one of the computers is accessing a device, you can check bit 6 of address
56576 ($DD00) on the other computer. Between bytes (sent either FROM the other
computer or TO the other computer), that bit will be clear. For each byte
transferred, the bit will go through nine set/clear cycles, returning to the
clear state. In my printer spooling program, I check that bit to sound a
chime when the printing is done. Of course, a delay will be required, to
ignore the times when the device is holding off the computer (e.g., while a
1541 read/write head is moving from track 1 to track 35).