Memory and Storage
Computer memory / storage can be classified in three ways; primary, secondary and off-line.
Primary
Primary memory is the computer’s main memory, which is directly accessible by the CPU and often much faster than secondary storage.
RAM will hold the loaded operating system, plus all running applications and files.
Examples of primary memory / storage:
- Random Access Memory (RAM) – solid state
- Read Only Memory (ROM) – solid state
Our Storage Devices page explains all about RAM and ROM.
Secondary
Secondary storage is a non-volatile medium that holds data until it is deleted or overwritten.
It is sometimes referred to as external memory and auxiliary storage. Secondary storage is where programs and data are kept on a long-term basis.
Examples of secondary memory / storage:
- Hard Disk Drive (HDD) – magnetic storage
- Solid State Drive (SSD) – solid state
Our Storage Devices page explains all about HDDs and SSDs, including their benefits and drawbacks.
Off-line
Off-line refers to non-volatile storage that can be easily removed from the computer. This is often used to transport data and keep backups for protection.
Examples of off-line memory / storage:
- CD, DVD, Blu-ray – optical storage
- USB Flash Drive – solid state
- Removable HDD / SSD
Our Storage Devices page explains all about the different types of optical media and flash drives.
