Primary memory
- Primary memory, also known as main memory or internal memory, refers to the memory that is directly accessible by the CPU.
- It is volatile memory, meaning that its contents are lost when the computer is powered off.
- Primary memory is responsible for storing data and instructions that are actively being used by the CPU.
- It is faster than secondary memory and is used to store temporary data, program instructions, and the operating system.
- Primary memory is divided into two types: RAM (Random Access Memory) and ROM (Read-Only Memory).
- RAM holds data and instructions that can be read from and written to by the CPU.
- ROM contains permanent instructions that cannot be modified, such as the computer's firmware.
- Examples of primary memory include cache memory, registers, and main memory (RAM).
Secondary memory
- Secondary memory, also known as external memory or auxiliary memory, refers to storage devices that are not directly accessible by the CPU.
- It is non-volatile memory, meaning that its contents are retained even when the computer is powered off.
- Secondary memory is used for long-term storage of data and programs.
- It is slower than primary memory but has larger storage capacity.
- Examples of secondary memory include hard disk drives (HDD), solid-state drives (SSD), optical drives, and flash drives.
Virtual memory
- Virtual memory is a memory management technique that allows the computer to use a portion of the secondary memory as an extension of the primary memory.
- It is a combination of physical RAM and a portion of the hard drive that acts as an overflow storage.
- When the physical RAM is full, the operating system swaps out less frequently used data and instructions to the virtual memory.
- Virtual memory provides the illusion of having more RAM than physically available, allowing programs to run smoothly.
- However, accessing data from virtual memory is slower compared to accessing data from physical RAM.
Real memory
- Real memory is another term for primary memory.
- It refers to the physical memory components that are directly accessible by the CPU.
- Real memory is contrasted with virtual memory, which is an extension of the primary memory using secondary storage.
- Real memory stores data and instructions that are actively used by the CPU, providing fast access to the information.
In conclusion, the memory inside the computer that is directly accessible by the CPU is called primary memory. It is divided into RAM and ROM, and it is responsible for storing data and instructions that are actively used by the CPU. Secondary memory refers to external storage devices, virtual memory is a memory management technique that utilizes a portion of secondary memory as an extension of primary memory, and real memory is another term for primary memory.