Secondary Storage

- Nonvolatile storage of digital data
- Magnetic or optical
- Magnetic media
   - Sequential access (tape) or direct access (HDD)
   - Hard disk drives
      - Metal disk with metallic coating
      - Disk spins at speeds of up to 7000 rpm
      - RAID – redundant array of inexpensive disks
   - Floppy disks
   - Magnetic tape
   - Zip disks and other magnetic storage alternatives

Optical Secondary Storage
- Compact disks (CDs)
   - 600 MB capacity
   - CD-ROM
   - CD-R
   - CD-RW
- Digital versatile disks (DVDs)
   - 2 – 17 GD capacity
   - DVD
   - DVD+/-R
   - DVD+/-RW