Primary Storage
Primary storage is a key component of a computer system that enables it to function. Primary storage includes random access memory (RAM), read only memory (ROM), cache and flash memory.
Primary storage (also known as main memory) is the component of the computer that holds data, programs and instructions that are currently in use.
Primary storage is located on the motherboard. As a result, data can be read from and written to primary storage extremely quickly. This gives the processor fast access to the data and instructions that the primary storage holds.
There are four types of primary storage:
1. read only memory (ROM)
2. random access memory (RAM)
3. flash memory
4. cache memory
The two main types of primary storage are ROM, which is non-volatile, and RAM, which is volatile. Nonvolatile memory keeps its contents even when the computer is switched off. Volatile memory loses its contents when power is lost.
Primary storage is comparatively limited in size, especially when compared with secondary storage. In a modern personal computer, primary storage is often around
4GB in size.
Secondary Storage
A secondary storage device refers to any non-volatile storage device that is internal or external to the computer. It can be any storage device beyond the primary storage that enables permanent data storage.
Most of the secondary storage devices used to be internal to the computer such as the hard disk drive, the tape disk drive and even the optical storage drive (CD-ROM, Blu-ray, and DVD) and floppy disk drive.
However, today, many secondary storage drives are frequently external, especially since the introduction of USB flash drives and plug-and-play devices.