1. Primary Storage
What is Primary Storage?
Primary storage is memory that is directly accessed by the CPU (the brain of the computer). This means the CPU can read data from and write data to primary storage very quickly, without having to go through any other components first.
There are two main types of primary storage:
- RAM (Random Access Memory)
- ROM (Read Only Memory)
Think of primary storage as the computer's "working desk" – it holds the things the computer is actively using right now.
Characteristics of Primary Storage:
- Fast access times: The CPU can get data from primary storage very quickly
- Small capacity: Primary storage typically holds much less data than secondary storage (for example, 16 or 32 gigabytes of RAM compared to 1 or 2 terabytes of secondary storage)
- Expensive: Because it's so fast, primary storage costs much more per gigabyte than secondary storage
- Mostly volatile: Most primary storage (except ROM) loses all its data when the computer is turned off
What is RAM?
RAM is the main working memory of a computer. It holds the data and instructions that are currently in use by the CPU.
Key Features of RAM:
- Volatile: This means all data stored in RAM is lost when the power is turned off. This is why you lose unsaved work if your computer crashes!
- Fast: RAM is much faster than secondary storage like hard drives, which is why the CPU uses it
- Read/Write: The CPU can both read data from RAM and write new data to RAM
- Larger capacity than ROM: Typically 4GB, 8GB, 16GB or more
- Directly connected to the CPU: This allows for very quick access
What does RAM store?
- Parts of the operating system that are currently running
- Programs that are currently open (like your web browser or word processor)
- Data that is currently being used or edited
- Files that are being worked on
Example: When you're watching a video on a smart TV, RAM stores the current video stream being played, the TV's volume setting, the channel you're watching, and any apps that are running in the background.