Comment by Mountain_Skies
10 hours ago
One of the biggest disappointments of the 8-bit era was the Commodore 128 not being able to use both the 8502 and Z80 CPUs in some kind of coprocessor setup.
10 hours ago
One of the biggest disappointments of the 8-bit era was the Commodore 128 not being able to use both the 8502 and Z80 CPUs in some kind of coprocessor setup.
The Commodore 128D has two 6502 CPUs. One is in the floppy drive and you can run software on it while the main 6502 ran something else.
That derives logically from the way Commodore implemented disks. If you bought a 1540 or 1541 (or any other Commodore drive) for a C-64 or VIC-20, it had an onboard 6502 to run the disk drive. The interaction between the computer and the disk drive was somewhat similar in concept to fetching a file from a network server.
This could be useful to save on costs in computer labs... my grade school used multiplexer boxes to share a single 1541 across four C-64's.
It was always awkward to do low level disk stuff by basically "remoting" into the drive to execute code.
was always a weird way to format a floppy...
1 reply →
I wrote code to do this between a C64 and a 1541 disk drive when I was in high school. It got me to the international science fair and (probably) earned me a full tuition scholarship for undergrad.
128D had 3 cpus :)