RAM is temporary storage that is volatile and clears when power is turned off, while ROM is permanent internal storage used to boot up a computer. Mass storage devices like hard disks and optical disks provide larger but slower storage than internal memory. Hard disks use magnetic disks to allow random access storage, while optical disks like CDs, DVDs, and Blu-ray use lasers to read serially accessed data at different storage capacities. Flash memory, memory cards, magnetic tapes, and floppy disks provide portable but slower storage options than internal memory. Backing up data involves copying it to a separate storage device for protection, while archiving removes old data to free up space.

1. Revision Session 2