Summary 📝

Secondary storage in computer systems refers to a type of storage used to hold data and programs that are not actively being used by the computer's central processing unit (CPU). 

Unlike the computer's primary memory (RAM), which is volatile and loses its content when the computer is turned off, secondary storage is non-volatile, meaning it retains data even when the power is off. 

Examples of secondary storage devices are hard disk drives (HDDs) and solid-state drives (SSDs). Secondary storage is essential because it allows users to store large amounts of data permanently, like documents, photos, and software, ensuring they are not lost when the computer is shut down. This extra storage space is crucial for accommodating data that cannot fit in the limited and temporary memory of the computer's RAM.

Key learning Points 📌

• Different storage devices suit different purposes, depending on speed, capacity, cost and portability.
  
  

• External hard drives offer high capacity at low cost—but are slower and easily damaged.
  
  

• Solid state drives (SSD) are fast, more durable and portable, but cost more per gigabyte.
  
  

• Optical discs (CD, DVD, Blu‑ray) are cheap for distributing data but have low capacity and slow access.
  
  

• USB flash drives (flash memory) are small, portable and reliable, but capacity and speed vary.
  
  

• For long‑term archival backups, magnetic tape can hold massive data but is slow to access.
  
  

Students should match storage type to application: e.g. SSD for OS, HDD for large storage, USB for portability, optical for distribution, tape for backups.