Memory acts as temporary storage, permanent storage is the HDD itself. Files are read from the HDD sectors based on their location kept in the File Allocation Table (FAT), loaded into RAM, manipulated by the user via keyboard and mouse and when the user saves the file, it is written to its permanent folder . storage space, the HDD. So, having an HDD that runs at 7200 RPM and has a 16MB cache becomes invaluable