Category:Kernal ROM

KERNAL (Keyboard Entry Read, Network, And Link) is the name of the ROM chip containing the base system code for the C64 (and most other Commodore 8-bit computers). On the C64 the Kernal is mapped from $E000 - $FFFF and contains all kind of I/O-routines for keyboard, printers, RS-232, screen, tape and drives. There have been several versions of the kernal ROM for the C64 which usually contained smaller bug fixes. For details regarding the kernals' internal routines please check the weblinks.

What makes the kernal for us a thing of major interest is the availability of replacements usually removing tape support and adding fast load, monitor or changed reset routines next to a few other features. Replacing the Kernal can be done by either adding a Kernal switch board to the C64 which allows toggling between several Kernals or by inserting a cartridge which replaces the Kernal. Of course when using the cartridge solution it might pose difficult to run e.g. a Freezer cartridge in parallel.

Kernal replacements such as Speed DOS, Jiffy DOS or ExOS usually work quite well together with a multifunction cartridge on the expansion port but of course there can be incompatibilities (which we love to document here whenever we are getting aware of them).

Some of the Kernal replacements will require a new ROM on the disk drive, a parallel cable or even an add-on board to speed up the disk drive but usually should operate at normal speed whenever the drive contains the standard ROM. The related articles as well as Related Hardware should resolve any remaining questions.