Secondary storage is a core topic in IB Computer Science because it explains how data is stored permanently. Unlike RAM, secondary storage is non-volatile, meaning data is retained even when power is switched off.
IB students are expected to understand the main types of secondary storage devices, how they work, and when each is used. The most important devices to compare are Hard Disk Drives (HDDs), Solid State Drives (SSDs), and Network Attached Storage (NAS).
What Is Secondary Storage?
Secondary storage is used to:
- Store operating systems
- Store software and applications
- Store user files and data
- Retain data long-term
It is slower than RAM but much larger in capacity and non-volatile.
Hard Disk Drives (HDDs)
HDDs store data using magnetic platters that spin at high speed.
Key characteristics:
- Mechanical components
- Large storage capacity
- Lower cost per gigabyte
- Slower access times compared to SSDs
Data is read and written using a moving read/write head, which causes delays due to physical movement.
In IB answers, HDDs are often associated with:
- Desktop computers
- Servers requiring large storage
- Backup systems
Their main disadvantage is slower performance and higher risk of mechanical failure.
