There are three main types of secondary storage: solid-state (SSDs, flash drives), optical (CDs, DVDs, Blu-rays), and magnetic (hard disk drives). Each has different characteristics that make it suitable for different applications.
Key points
Definition:Solid-State Storage: uses electrical circuits with no moving parts (e.g. SSDs, USB flash drives). Very fast and durable.
Definition:Optical Storage: uses a laser to read/write data on discs (e.g. CDs, DVDs, Blu-rays). Cheap per disc but low capacity.
Definition:Magnetic Storage: uses magnetised regions on spinning platters (e.g. HDDs). High capacity and cheap per GB, but has moving parts.
Solid-state: no moving parts, fast read/write, lightweight, durable, but expensive per GB.
Optical: very cheap per disc, small and lightweight, but low capacity and easily scratched.
Magnetic: high capacity, cheap per GB, but bulky, fragile (moving parts), and slower than SSDs.
Exam Tip:When comparing storage types, always relate to the SPECIFIC CHARACTERISTICS asked about (capacity, speed, portability, durability, reliability, cost).
Exam Tip:For cost, say 'cheaper per GB' or 'cheaper cost per unit of data' — NOT just 'it is cheap to buy'.
Common Mistake:Saying SSDs have 'unlimited lifespan' or 'more longevity than magnetic'. SSDs have a limited number of write cycles.