The ever-so-popular EPYX Fast Load cartridge for the
Commodore 64 included a DOS wedge (adding commands such as
$ to list the files on a disk,
/filename to load a file and
show the disk error status) and a fast loader that sped up
certain disk operations, such as loading files from the disk. There
were many other cartridges, KERNAL ROM replacements, etc.
with similar functionality.
Are there any freely usable and modifiable open source projects that offer either or both of these functionalities? I'm interested in both pure software solutions (presumably loaded from disk) and solutions that involve hardware so a cartridge could be used. (The Epyx Fast Load had not only the software in ROM, but also special support in the cartridge to allow it to "disappear" after a short time, restoring RAM to the $8000-$9FFF address range so that programs could use it.)
This is intended for use on real hardware as well as emulators, and ideally the software should work with an SD2IEC as well. Also, cross-build from a Linux platform would be greatly appreciated, though this is probably something one could add oneself if the standard build platform were a C64 or something else.