The Need for Secondary Storage
- Computer systems need both main memory and secondary storage to operate
- Both types of storage play a crucial role in the operation of a computer system
- A quick comparison of main memory and secondary storage shows:
| Main memory | Secondary storage |
| Volatile (with the exception of ROM) | Non-volatile |
| Small capacity | Large capacity |
Why do you need secondary storage?
- A computer needs secondary storage for long term storage of programs and data that are currently not in use
- Secondary storage is needed as ROM is read only and RAM is volatile
- Secondary storage holds the programs and data whilst the computer is turned off (non-volatile)
- Performance of secondary storage is slower than primary storage but capacity is much higher which makes it perfect for backup & archive of data files
What are the characteristics of secondary storage?
- Capacity - What is the maximum amount of data that can be stored?
- Speed - How fast can data be read from and written to? (R/W)
- Cost - How much does it cost?
- Portability - How easy is it to move around? What is the physical size? Weight?
- Durability - How robust is the storage?
- Reliability - What is the probability that the device will consistently perform its function?
Worked example
A games console has secondary storage.
State, using an example, why the games console needs secondary storage [2]
How to answer this question
- They keyword is 'why', why does a games console need secondary storage? give an example, do not just describe what secondary storage is!
Answer
- To store data once the power is turned off / permanently // for non-volatile storage
- Examples could include:
- Storing games
- Save games
- User data / profiles
- Downloaded content / applications / updates
