RETRO Innovations



JiffyDOS is a Disk Operating System (DOS) enhancement which gives your C-64 or C-128 the disk access speed it has always needed. A chip-for-chip replacement for the Kernal ROM in your computer and the DOS ROM in your disk drive(s), JiffyDOS achieves levels of performance and compatibility unmatched by other disk speed-enhancement products. Outstanding speed, solid compatibility with virtually all hardware and software, and a new set of desperately-needed commands and features, gives your system a new lease on life and the power to compete with today’s newer, more-expensive machines.

JiffyDOS should not be confused with Cartridges, Turbo ROMs, Burst ROMs or “Parallel” systems. Ultra-high-speed multi-line serial technology enables JiffyDOS to outperform these products without any of their inherent disadvantages. JiffyDOS leaves all ports on your computer open, works with virtually all software, speeds up PRG, SEQ, REL and USR files, and does not require any extra cabling. Owning JiffyDOS also gives you access to some of the best product support available.

JiffyDOS support is included natively in uIEC and all other sd2iec-based solid state drive solutions for the Commodore.  Thus, by installing JiffyDOS in your C64 or C128, you can immediately enjoy all JiffyDOS functionality when using these devices.

Authorized Sales

At this time, there are 2 authorized sales channels for JiffyDOS:

No other distributors are currently licensed to offer JiffyDOS at this time.  Please help us maintain the ability to offer licensed JiffyDOS copies by purchasing from one of the above sales channels.


Below are the installation guides and manual for JiffyDOS. These are provided free of charge to those already owning JiffyDOS and/or those wanting to understand JiffyDOS commands.

I want to thank David Haynes for scanning some of these documents and Shane Fell for the reproduction of the JiffyDOS overlays. As for the other documents and the searchable manual, I’m trying to track down the scanners/authors to thank them.

Over time, I hope to OCR and re-typeset these documents. If you would like to help with this effort, please let me know. As well, the list of documents is currently incomplete. If you can help with copies of documents not yet in the archive, please let me know.

PLEASE LINK ONLY TO THIS PAGE, as the underlying manual and installation guides may move in the future. With the exception of the overlays, PLEASE DO NOT REHOST THESE DOCUMENTS AT OTHER LOCATIONS.

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