Secondary storage

• What is Secondary storage?

  • Non-volatile data storage
  • Needed to store files + programs for later use
• What must secondary storage be?

  • Non-volatile
  • Low cost
  • High capacity
  • Reliable
• MAGNETIC STORAGE

  • Example: Hard disk drive (HDD)
  • Moving parts
  • Stores data magnetically on metal disks
  • Can be noisy
  • Long lasting, reliable, high capacity storage at low cost
• SOLID STATE STORAGE

  Example: Solid state drive

  • Flash memory - zero moving parts
  • Faster data access than HDDs due to no moving parts
  • Quiet/silent, low power consumption
  • Robust, lightweight, compact - ideal for portable devices
  • Smaller capacity than HDDs, cost per unit of storage higher
• PORTABILITY: HDD vs SSD

  • HDD: Low
  • SSD: high
• DURABILITY + RELIABILITY: HDD vs SSD

  • HDD: Damaged by impacts, long read/write life
  • SSD: Shock resistant, limited rewrites
• OPTICAL STORAGE

  -Uses properties of light to store data

  -Most common medium - Optical disks: CDs, DVDs, Blu-ray disks

  CDs DVDs Blu-Ray

  ------------------------------>

  (lowest) (highest)

  Capacity
• ADVANTAGES + DISADVANTAGE OF OPTICAL STORAGE

  • ADVANTAGES: very cheap (per GB), portable, not damaged by water or shocks
  • DISADVANTAGES: Low capacity per disk, poor reliability compared to flash storage devices, scratched easily, very slow