The Need for Primary Storage
- Computer systems need both primary and secondary storage to operate
- Both types of storage play a crucial role in the operation of a computer system
- A quick comparison of primary and secondary storage shows:
| Primary | Secondary |
| Volatile (with the exception of ROM) | Non-volatile |
| Small capacity | Large capacity |
Why do you need primary storage?
- A computer needs primary storage because access times are considerably faster than secondary
- This means the time taken to complete operations such as the Fetch-Execute Cycle is dramatically reducedĀ
- Primary storage holds the data and instructions that the CPU needs to access whilst the computer is turned on
- Due to the fast access times, primary storage is used as short term, working memory, in hardware that is directly connected to the CPU such as RAM, and components that reside inside the CPU such as Cache and Registers
- Performance of primary storage means a much higher cost which limits the amount that is used
- For example, RAM is commonly purchased in 16 or 32 gigabytes whereas secondary storage such as a hard drive is in terabytes
