kottke.orgJul 12
Not a joke: there is a new Commodore 64 coming out. “The glowing, translucent Commodore 64 isn’t a software emulator — it’s the first official C64 in over 30 years, with a few new tricks.” You can preorder now & cancel before shipping for a full refund. https://www.commodore.net/
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Show threadPaul ChernoffJul 12

@kottke @WarnerCrocker I am wondering about the processor. My understanding is that the C128 bombed is that it could not run C64 games which depended on a bug in the C64’s 6592 processor. The C128 had a more advanced chip that did not have the bug and thus you had incompatibility. There was a C64 mode (did that use a 6502 chip?), and C128 mode, and a CPM mode.

If they are not using emulation in this new model, what powers it and how does it run old software?

Show threadLeelooJul 12

@paulc @kottke @WarnerCrocker
I never heard of a single (64) game that didn't work on the 128. One could still exist, I wrote a program (in basic even) that could detect if it was running on a 128, so it could be done.

The 128 bombed because it was expensive and ran 64 software so perfectly, that developers wrote software for the bigger 64 market and almost nothing took advantage of the 128s improvements, so buying one was a waste of money.

Heck, there was an office suite that took advantage of the autoboot feature on the 128, then switched to 64 mode and continued loading.

Show threadPaul ChernoffJul 12

@leeloo @kottke @WarnerCrocker you got me looking. I’m not sure what I am remembering. I did see something in Wikipedia was a different issue and very few programs were affected.

A handful of C64 programs write to $D030 (53296), … This memory-mapped register, unused in the C64, determines the system clock rate. Since this register is fully functional in C64 mode, an inadvertent write can scramble the 40-column display …

Show threadLeelooJul 12

@paulc @kottke @WarnerCrocker
Heh, that was exactly the trick I figured out to tell if my program was running on a 64 or 128. Switch to 2 MHz, run a small loop, check how long it took, switch back to 1MHz.

It didn't scramble the display, it switched it off (showed the border color) lile when loading from tape.

Oh, and no, the 128 did not have a 6502 or 6510 cpu, 64 mode used the 8502 main cpu. It did have two cpus, but the other cpu was a Z80 for CP/M.

Show threadPaul Chernoff

@leeloo @kottke @WarnerCrocker I think the wiki article did mention a 6502 but only as a disk controller. I had forgotten that the main CPU was an 8502 which I guess was just a faster 6502.

I somewhat missed out on those specific days of computing. I was in Grad school in the early 80s so no money for a computer, and then bought a Mac in 1985 once I had a job. I had played with a Mac in 1984 and used and Apple /// for one course.

Jul 12 at 10:23pmWeb
Show threadPaul ChernoffJul 12
@leeloo @kottke @WarnerCrocker I will look for my book on the history of Commodore, which is a recommended read for people interested in the early years of personal computing.
Show threadLeelooJul 13

@paulc @kottke @WarnerCrocker
That's (almost) correct, the Commodore floppy drives used a 6502 cpu. So I guess technically the 128D (the one with built in floppy drive) would have had three cpus.

Not a controller as we think of it, though, the computer had no floppy controller, the floppy drive had its own cpu. Which means if you had four floppy drives, you had four extra cpus - which is why a Commodore floppy drive was more expensive than the computer.

Technically, the floppy drive firmware did support controlling two drives with one cpu, but that was only used on the Commodore PET.