Commodore DOS

Commodore DOS, also known as CBM DOS, is the disk operating system used with the Commodore 8-bit computers. Unlike most other DOSes, which load from disk into a host computer memory and run there, CBM DOS runs internally inside the disk drive itself, residing in ROM chips and executed by one or more dedicated MOS 6502 family processors, so that data transfer between a Commodore computer and its disk drive resembles a small local area network connection more than a typical disk-to-host transfer. This description is adapted from Wikipedia contributors under CC BY-SA 4.0; changes were made. https://creativecommons.org/licenses/by-sa/4.0/