This document discusses secondary storage devices and non-volatile memory. It defines secondary storage devices as any storage beyond the primary storage that enables permanent data storage, including magnetic tapes, floppy disks, DVDs, and USB drives. Non-volatile memory is computer memory that can retain stored information without power, such as ROM, flash memory, hard disks, and optical discs. Examples of volatile memory that requires power to maintain storage include RAM and cache memory. The document contrasts volatile and non-volatile memory and explains how secondary storage saves data after the primary storage temporarily holds it.