stereo wiring, confused.

[htyei]

I'm looking at the SVX Sound Installion wire diagrams am in wonder which power conenct is which?

The SVX diagram shows two power connectors:

Primary power &
Memory power


My head unit has a

primary power &
acc power



At first I assumed primary goes with primary, but memory power has connotations that acc power does not.

My head unit also has one wire to cd illumination, Does that mean it doesn't need to be grounded?(like the stock unit)