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Give your Commodore 64 new life with an SD card reader
Posted on: 2012-08-01 21:22:38

This August marks the 30th anniversary of the most successful computer model in history. One company put personal computers into the people's homes, and launched an entire industry overnight. For an entire decade, despite attempts at marketing improvements, the original platform stood the test of time, virtually unchanged. Even today, the Commodore 64 is celebrated by a community of hobbyists.

In honour of the anniversary month, here are some up to date instructions on how to read old data from the disks. Floppy disks only have a usable lifespan of 10 years, and most of them in my collection are over 25 already. At this point, the chemical binder between the magnetic particles and the plastic substrate is degrading, and the data can literally fall out of the disks. Fortunately, up to date software from the opencbm project tries very hard to read the data and can often succeed when a disk appears to be unusable when connected to a C64.

Here's what you need to read your floppy disk into your PC:

  1. A commodore 1541 disk drive, in good condition, and power supply.
  2. The drive cable.
  3. This ZoomFloppy adapter
  4. a USB cable.

In addition, if you want to read disk images from an SD card hooked into the real Commodore 64, you will need the uIEC adapter, which can be substituted for a real floppy drive.

Transferring floppy disks to the PC

I want to scan in my copy of Jumpman so its digital bits are preserved.

This copy is totally genuine EPYX product. At least that's what they guy at the swap meet told me, behind the K-mart.

You have to download the special build of the opencbm software from here. I am using the windows version. Read the manual very carefully to install the driver, before you can use the command line tools.

Then, plug the ZoomFloppy into the Commodore drive using the commodore cable (make sure the drive is off!), and into your PC using a USB cable.

Confusingly there's some empty ports. If you want, you can hook other things into it for decoration, I guess.

Now we turn on the drive, put in the disk and cross our fingers. From a command line, I type:
d64copy -r 16 8 "jumpman.d64"

This means:

  • Retry bad blocks up to 16 times before giving up.
  • Copy from device #8. Remember, on Commodore, the first floppy drive was always device 8.
  • Copy the contents of the disk to the file called jumpman.d64

A minute later, and it is done. Unfortunately, we have a bad sector. Hopefully it is in an unused part of the disk, or in some graphics that won't cause a crash.

At this point, we can run the game in the Vice emulator (On windows this distribution seems to work).

Running games from SD cards

No serious commodore enthusiast is without his or her SD card reader. I happen to have the uIEC which Jim Brain soldered together right in front of me at the World of Commodore 2011 in Toronto.

It has to plug into the back of the Commodore, presumably for power, and then the drive cable goes into it as well. Then, it is ready to act exactly like a floppy drive.

But how do folders work?

You can just about fit all the Commodore software in existence onto one card, so how do you access it? You can switch disk images by sending special drive commands to it in BASIC. I've placed the jumpman.d64 file on the SD card. Here is the command to switch to it:


There are many other commands for the uIEC. It has some buttons on the circuit board that let you swap disks on the fly without typing commands, but these have to be set up by listing them in a special file. All the other commands are described here.

A major drawback of the uIEC is that while it emulates the standard Commodore drive operation, the commodore 1541 drive was actually another computer that you could load programs on and run. Some programs did this for copy protection or to implement custom fast-loaders. More recently the retro demo-scene uses it for extra storage and computing power. I was disappointed when the Second Reality demo didn't work.

Well, I have Jumpman loaded anyway, so off to an evening of retro fun.

The cheater method

Of course, if you don't want to go to all this trouble, you could obtain just about any software you can think of using pokefinder. Just Bing it.

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