## What is Secondary Storage?

Secondary storage is used for long-term data storage. It stores data not currently in use by the CPU. It is slower than primary storage but has much larger capacity.

## Types of Secondary Storage

### Magnetic Storage

Uses magnetic fields to store data. Example: Hard Disk Drive (HDD).

### Optical Storage

Uses lasers to read/write data. Examples: CDs, DVDs.

### Solid-State Storage

Uses flash memory with no moving parts. Faster and more reliable. Examples: SSDs, USB drives.

## Hard Disk Drive (HDD)

An HDD stores data using spinning disks called platters. Data is stored magnetically and accessed by read/write heads.

## Optical Discs

Data is stored as pits and lands on the surface of the disc. A laser reads this data.

Pits represent 0 and lands represent 1.

## Choosing the Right Storage Device

- Capacity
- Speed
- Cost
- Portability
- Durability
- Reliability

## Quick Quiz

Which storage type has no moving parts?