3 ms·

>how Commodore cheapened out by replacing the mechanism manufacturer's (Shugart) controller with a design of their own. I'm not sure it was wise, but "cheapene

by tyingq 3y ago

>how Commodore cheapened out by replacing the mechanism manufacturer's (Shugart) controller with a design of their own. I'm not sure it was wise, but "cheapened out" doesn't seem right either. The C64 disk drives have their own 1MHZ 6502 CPU inside them, so they have roughly the same amount of CPU as the C64 itself.

wussboy 3y ago
But can it run Doom? I would not be surprised at all to find someone has found a way to double the C64’s processing power with it.
- tyingq 3y ago
  The 6502 in the 1541 is somewhat hobbled having only 2k of RAM. Though you can solder a bigger SRAM on the board.
- dezgeg 3y ago
  Here's a demo running on just the drive: https://cdm.link/2021/07/freespin-is-a-demo-made-for-the-commodore-1541-no-not-the-computer-just-the-floppy-drive/ https://cdm.link/2021/07/freespin-is-a-demo-made-for-the-com...
  - wussboy 3y ago
    Hilarious!
ataylor284_ 3y ago
Commodore had bought out MOS by this point and manufactured 6502 chips themselves, so the drive CPU was "free" in a sense. Also it's worth noting that the Commodore DOS talked about in the article was implemented and ran entirely on the drive, not the host computer. Commodore computers only understood a simple serial protocol and DOS commands like rename, delete or format disk were just sent as text commands on the serial command channel, which were interpreted and run by drive itself. The computers had no concept of a filesystem at all: displaying the disk directory involved a hack where the drive would construct a fake BASIC program and stream it to the computer when a special filename "$" was loaded. That's why displaying the disk directory on a Commodore computer would clobber any BASIC program in RAM. A common blunder was to list the directory before saving and losing your work. While the disk drives were smart, the tape drives were dumb. Tape drives came first and were designed along side the computer architecture starting with the PET. The disks were an add on later once disk drives caught on as the home computer medium of choice. The computers actually had a significant amount of precious ROM space dedicated to tape drive operation which was completely wasted in the later C64 timeline when most users were using disks exclusively. Some later ROM replacements like the excellent JiffyDOS system repurposed the tape code in their ROMs to provide a built in fast loader and DOS wedge (a whole other rabbit hole).
patja 3y ago
I still remember having my mind blown at a Pirates of Puget Sound party in the 80s where there were banks of 1541 drives connected in pairs happily copying disks with no C64 connected to the drives. Just insert two disks and it would copy from A to B. That was when I realized the 1541 drives weren't just drives, they were computers themselves.

by tyingq 3y ago

wussboy 3y ago

But can it run Doom? I would not be surprised at all to find someone has found a way to double the C64’s processing power with it.

tyingq 3y ago
The 6502 in the 1541 is somewhat hobbled having only 2k of RAM. Though you can solder a bigger SRAM on the board.
dezgeg 3y ago
Here's a demo running on just the drive: https://cdm.link/2021/07/freespin-is-a-demo-made-for-the-commodore-1541-no-not-the-computer-just-the-floppy-drive/ https://cdm.link/2021/07/freespin-is-a-demo-made-for-the-com...
- wussboy 3y ago
  Hilarious!

ataylor284_ 3y ago

Commodore had bought out MOS by this point and manufactured 6502 chips themselves, so the drive CPU was "free" in a sense. Also it's worth noting that the Commodore DOS talked about in the article was implemented and ran entirely on the drive, not the host computer. Commodore computers only understood a simple serial protocol and DOS commands like rename, delete or format disk were just sent as text commands on the serial command channel, which were interpreted and run by drive itself. The computers had no concept of a filesystem at all: displaying the disk directory involved a hack where the drive would construct a fake BASIC program and stream it to the computer when a special filename "$" was loaded. That's why displaying the disk directory on a Commodore computer would clobber any BASIC program in RAM. A common blunder was to list the directory before saving and losing your work. While the disk drives were smart, the tape drives were dumb. Tape drives came first and were designed along side the computer architecture starting with the PET. The disks were an add on later once disk drives caught on as the home computer medium of choice. The computers actually had a significant amount of precious ROM space dedicated to tape drive operation which was completely wasted in the later C64 timeline when most users were using disks exclusively. Some later ROM replacements like the excellent JiffyDOS system repurposed the tape code in their ROMs to provide a built in fast loader and DOS wedge (a whole other rabbit hole).

patja 3y ago

I still remember having my mind blown at a Pirates of Puget Sound party in the 80s where there were banks of 1541 drives connected in pairs happily copying disks with no C64 connected to the drives. Just insert two disks and it would copy from A to B. That was when I realized the 1541 drives weren't just drives, they were computers themselves.