1. Storage device
1.1. harddisk
1.1.1. RAID
1.1.2. network attached storage
1.2. Flash Memory Storage
1.2.1. Solid state drives
1.2.2. CompactFlash
1.2.3. Secure Digital
1.2.4. Secure Digital High Capacity
1.2.5. microSD
1.2.6. microSDHC
1.2.7. xD Picture Card
1.2.8. Memory Stick
1.2.9. Memory Stick Micro (M2)
1.2.10. USB flash drives
1.2.11. ExpressCard module
1.3. Could Storage
1.4. Optical Disk
1.4.1. CD
1.4.1.1. CD‐R
1.4.1.2. CD‐RW
1.4.1.3. Archive disc
1.4.1.4. Picture CD
1.4.1.5. CD‐ROM
1.4.2. DVD
1.4.2.1. DVD-ROM
1.4.2.2. Blu-Ray
1.5. Others
1.5.1. Tape
1.5.2. magnetic stripe card
1.5.3. Microfilm
1.5.4. Enterprise storage
2. User type
2.1. Home user
2.1.1. 320 GB hard disk
2.1.2. Cloud storage
2.1.3. Optical disc drive
2.1.4. Card reader/writer
2.1.5. USB flash drive
2.2. Power User
2.2.1. 2.5 TB hard disk
2.2.2. Cloud storage
2.2.3. Optical disc drive
2.2.4. USB flash drive
2.2.5. Portable hard disk for back up
2.2.6. USB flash drive
2.3. Small Office/Home Office user
2.3.1. 1 TB hard disk
2.3.2. Optical disc drive
2.3.3. Cloud storage
2.3.4. External hard disk for backup
2.3.5. USB flash drive
2.4. Mobile
2.4.1. 250 GB hard disk
2.4.2. Cloud storage
2.4.3. Optical disc drive
2.4.4. Card reader/writer
2.4.5. Portable hard disk for backup
2.4.6. USB flash drive
2.5. Enterprise User
2.5.1. (desktop computer)
2.5.1.1. 1 TB hard disk
2.5.1.2. Optical disc drive
2.5.1.3. Smart card reader
2.5.1.4. Tape drive
2.5.1.5. USB flash drive
2.5.2. (server or mainframe)
2.5.2.1. Network storage server
2.5.2.2. 40 TB hard disk system
2.5.2.3. Optical disc server
2.5.2.4. Microfilm or microfiche