The uIEC and JiffyDOS

One of the most fascinating things I discovered in recent years is the fact that people are still developing new hardware for the Vic 20, Commodore 64 and 128. One such product is the uIEC, which allows me to use a modern SD card with my Commodore 64 as though it were (to the Commodore 64) a gigantic 1541 disk drive. This means dealing with things that the Commodore 64 was never designed to handle, like directories. Floppies for the Commodore 64 were of such small capacity, directories and sub-directories were unnecessary; a person would have a collection of disks, each one representing what we would consider today a directory. IMGP5959

The Commodore 64 and its brethren are flexible enough to be able to deal with concepts like directories through the use of complicated commands. For example, to change into a directory called “MUSIC,” one would need to type:

OPEN 15,10,15,”CD:MUSIC”:CLOSE 15

Cumbersome and difficult to remember, most users would load in a DOS wedge, which was a program Commodore offered with its 1541 disk drives. Load that, and the same can be accomplished by typing in:


I opted instead to use my Cinemaware Warp Speed cartridge, which incorporated an improved set of commands. For example, for getting a directory with the DOS Wedge, one would type in @$, whereas with the Cinemaware cartridge, I only needed to type in $. More importantly, when it came to changing the drive number, the Cinemaware cartridge simply required me to type in R8 if I wanted to change the uIEC to device 8. The uIEC defaults as drive number 10, which is fine if you’re just using it to transfer files and disk images to floppy disks, but is a pain when dealing with software that is written to run specifically from drive 8. There are a large number of programs in the Commodore 64 library that are written to run from drive 8.

The other thing about uIEC is that it runs at the same speeds as the 1541, which was (and still is) very slow. In fact, my main reason for buying the Cinemaware Warp Speed cartridge back in the day was to speed up my disk drive access. Accelerator cartridges were a popular accessory on the Commodore 64, because it really was horrible how slow it was. I figure Commodore designed it to be used with a cassette tape drive, and disk drives were more of an afterthought. IMGP5958

Unfortunately, the uIEC is not accelerated by an accelerator cartridge. As it turns out, there really is only one way to get it to run at modern day SD card speeds, and that’s with JiffyDOS. JiffyDOS is a chip that replaces Commodore’s original DOS chip. It allows all disk drives and devices like the uIEC to run as fast as possible, which is many times faster than stock. It also incorporates the DOS wedge commands. These commands aren’t as intuitive as those in my Cinemaware Warp Speed cartridge when it comes to changing the drive number, so I decided to write this blog post so I could have something to refer to.

Changing the drive number

  1. First, I press CONTROL-D to make sure it’s set to drive 10.
  2. I type in @”U0>{control-h}” to set the drive number to 8. I use CONTROL-I to set to drive number 9, and CONTROL-J to set to number 10.
  3. I verify with CONTROL-D to make sure the drive number has been changed.

Copying a fileIMGP5957

  1. First, I set the destination drive. If I’m copying from the uIEC to a floppy, I’ll leave the disk drive at 8 and the uIEC as 10. The command is @X8 to set drive 8 as the
  2. I then get a directory of my files; I use CONTROL-D to switch to the appropriate drive, then @$ to pull up a directory listing.
  3. I cursor up to the file I wish to copy. I put an asterisk * next to the file I wish to copy, and press RETURN. The file gets copied.

There are command summaries available at various web sites for everything else, but these two issues seem to be overlooked on the ones I’ve found. Writing this blog post will ensure that, should I forget how to do this again from not using my vintage computers for a period of time, I’ll know exactly where to look.

One Reply to “The uIEC and JiffyDOS”

  1. I could not find a way of contacting you more directly so I will have to do it here: I saw your Jumpdisk archive. I have four 1987 issues which are not in your archive. If you are interested in copies and/or scans let me know. My only price in exchange is that you grant me access to your collection. There’s many issues there that I have never seen.

Leave a Reply

Your email address will not be published. Required fields are marked *