Primary memory

Memory is physically organized as a large number of cells that are capable of storing one bit each. Primary memory is comprised of DRAM (Dynamic RAM) and provides the actual working space to the processor. Primary memory is also known as Main memory or Internal memory, is the area in a computer which stores data and information for fast access.

Primary memory is the main memory of the computer which can be directly accessed by the central processing unit, whereas Secondary memory cannot be accessed directly by a CPU or processor. Secondary memory refers to the external storage device which can be used to store data or information permanently. The memory devices used for primary memory are semiconductor memories.

Generally, primary memory has a storage capacity lesser than secondary memory and greater than cache memory.

As soon as a computer starts, primary memory loads all running applications, including the base operating system (OS), user interface and any user-installed and running software utility. A program/application that is opened in primary memory interacts with the system processor to perform all application-specific tasks.

Random Access Memory (RAM) is primary-volatile memory and Read-Only Memory (ROM) is primary-non-volatile memory. The processor accesses all memory addresses directly, irrespective of word length, making storage and retrieval fast. RAM is the fastest memory available and hence most expensive.
Primary memory