I am also surprised at Grumpy_Mike, mowcius, and MikMo for -not- knowing this.
The prblem with being old is that people are always inventing names for stuff you did years ago before they had names. Here is a picture of my first Single Board computer, the board in question was a piece of floor board, and the year was 1975. It had 256 bytes of RAM and no ROM.
The difference between a controller and computer is a matter of the architecture, Harvard:-
Separates data and programming in different spaces. Where as Princeton architecture von Neumann architecture - Wikipedia is what you would call a "proper computer"
This makes no distinction between data and program apart from the context in which the CPU encounters it. Therefore with the board above it was able to take it's own code and turn it into notes. So it played it's own code, something you can't do with the unmodified Harvard architecture.