With the rise of modern storage solutions (Ultimate 64, TheC64 Maxi, MiSTer FPGA), you might wonder if jiffydos-c64.bin still matters.
To see how to install and configure JiffyDOS on a modern C64 Ultimate system:
C.M.R. and later CMD sold JiffyDOS as a commercial product. After CMD closed in the early 2000s, rights passed through various hands. Today, (via Retro Innovations) still sells licensed JiffyDOS ROMs and kits. jiffydos-c64.bin
The file jiffydos-c64.bin likely contains the binary data for JiffyDOS, possibly a version specifically compiled or modified for use on the Commodore 64. This could be:
The original C64 KERNAL checks a byte at $028A to see if a fast-load cartridge is present. JiffyDOS bypasses this entirely—it replaces the LIST , LOAD , and SAVE vectors with optimized assembly that uses and reduces bus turn-around times. With the rise of modern storage solutions (Ultimate
JiffyDOS remains the gold standard for speed on real floppy drives, even as SD2IEC and Pi1541 replace spinning rust.
| Solution | Type | Speed | Availability | |----------|------|-------|---------------| | | Hardware/ROM | Slightly faster than JiffyDOS | Commercial, rarer | | Turbo Trans | Software (PRG) | 2-3x faster | Free, but no permanent KERNAL replacement | | CBM-FAST (Mike J. Henry) | ROM replacement | 4-5x | Open source (GitHub) | | SJLOAD (for SD2IEC) | Patching | 6x+ with SD2IEC | Open source, requires SD2IEC drive | After CMD closed in the early 2000s, rights
The answer is . FPGA cores often re-implement the 1541 drive and allow you to load custom KERNALs and drive ROMs from a single .bin file. The upcoming Ultimate 64 Elite and MEGA65 have built-in support for injecting JiffyDOS at boot.
Furthermore, open-source hardware projects like the cartridge allow you to mount jiffydos-c64.bin as a CORE update, turning the cartridge into a KERNAL switcher.
: For full speed, you must use both the jiffydos-c64.bin (computer) and a corresponding drive ROM image (e.g., for the 1541 or 1571 drive).