Hardware roles: a simplified model
Storage --load instructions and data--> RAM
CPU --execute instructions using working data--> RAM
RAM --save file data--> Storage
OS: manages programs, memory, files and devices.

The CPU executes instructions. RAM holds active working data.
Ordinary RAM loses its contents when power is removed.
Storage retains saved files without continuous power.
Loading and saving move data between these roles.
Real computers also use caches and disk-backed virtual memory;
this model does not show every mechanism or physical connection.