Classic Computer Magazine Archive COMPUTE! ISSUE 124 / DECEMBER 1990 / PAGE 102


JiffyDOS 6.0, a worthy successor to an excellent version 5.0, is a set of ROM chips for the 64 or 128 and disk drive. The 128 set contains three chips; the 64 set contains two. JiffyDOS speeds up disk access for all functions except FORMAT and VALIDATE and offers an enhanced wedge that works in conjunction with an onscreen directory. JiffyDOS ROMs are available for all Commodore and most compatible drives.

JiffyDOS offers this increased speed without tying up any ports, and it doesn't require additional cables. One can switch easily between JiffyDOS and the computer's standard configuration, and its price is reasonable.

JiffyDOS is particularly useful when using music synthesizers where the cartridge port is occupied with a MIDI interface. It's also ideal when used with cartridge word processors and modems that tie up the parallel port.

Installation is quite simple. It is aided by the clearest and most comprehensive set of instructions that I've seen, and its manual is a model of clarity. The installation process took me 90 minutes. This included testing and installing defeat switches for both the 64 and 1541 disk drives. The most challenging task was drilling holes for the two switches. I actually used my soldering iron to burn the holes through the plastic case.

One note of caution! Check first before buying JiffyDOS to see if your ROM chips are soldered into their sockets. If this is the case, do not attempt the conversion. I haven't encountered this situation, but it is a good idea to open your 64 and check first.

As with JiffyDOS 5.0, version 6.0 includes programmed function keys, a listing freeze, and an OLD command. Major enhancements with 6.0 are user-programmable function keys, an enhanced list freezer/stepper, a built-in two-drive file/disk copier, and the ability to set sector interleaves. This last feature permits you to achieve through experimentation the ultimate disk access drive speed for a particular program on your model disk drive.

Two of these features require comment. Very rarely do the function keys come programmed the way I like them. JiffyDOS is probably the exception. (The keys are configured differently in versions 5.0 and 6.0.) You can configure them any way you wish in the new version, with unlimited characters per function key. A welcome addition to the documentation is a function-key template for both the 64 and 128.

The bad news is that you have to create, load, and run a program to load the custom functions. A short model in BASIC is given in the manual, and no particular programming skill is required to make the modification. But the fact remains that you can't change a few crucial function key definitions in direct mode whenever you wish.

Jiffy DOS supports Commodore RAM expansion units (REU), allowing you to access an REU just like a disk drive. For two-drive systems, the flexible dual copier should prove useful. You can easily specify source and destination drives and freely mix drive types, including those not modified with Jiffy DOS.

Several other features common to Jiffy DOS 5.0 and 6.0 are noteworthy. Onscreen directories are never overwritten by the computer, and all JiffyDOS wedge commands may be used from within BASIC programs. In version 6.0, these commands include the expanded copier commands. You can even write your own custom copy programs. Text and program files can be read from disk directly without corrupting memory. These files and the screen can be dumped directly to a printer, also without affecting memory. This process is much easier, however, with version 6.0.

I do have one small bone to pick. Although Jiffy DOS offer a purportedly but-free, save-with-replace routine, you cannot use it from the onscreen directory. You must first scratch a file and then resave. Unfortunately, it is quite inconvenient to do both of these things from a single directory.

If you are looking for a moderately priced, full-featured ROM replacement, Jiffy DOS is for you. Creative Micro Design supports its products well, and it is one of the few companies still actively developing accessories for the 64 and 128. This innovative company deserves the support of Commodore users.


Ease of Use ****
Documentation *****
Features ****
Innovation ****

Commodore 64, 128, or SX-64—$59.95 for two-ROM 64 set; $69.95 for three-ROM 128 set; $29.95 for additional drive ROMs

P.O. Box 789
Wilbraham, MA 01095
(413) 525-0023