Computer memory

Computer memory comprises hardware and data structures that store information for a computer to use, temporarily during processing or persistently between sessions.

Random-access memory: Semiconductor memory that lets a processor read or write data at nearly any address with similar speed. It is the main working memory for active programs and data.
Memory address: A numeric identifier that specifies a location in a computer's addressable memory space. Processors and software use addresses to locate data and instructions.
Dynamic random-access memory: A volatile semiconductor memory that stores each bit in a capacitor and periodically refreshes it. It provides the dense, economical main memory used in most computers.
Memory management: The allocation, tracking, protection, and release of memory used by software and operating systems. It determines how competing programs share available memory safely.
Read-only memory: Nonvolatile memory designed chiefly for reading stored data, often used for firmware. It holds instructions that must remain available when ordinary working memory is empty.
Memory hierarchy: An arrangement of storage levels ordered by access speed, capacity, and cost per bit. Computer memory operates across levels rather than as one uniform store.
Static random-access memory: A volatile semiconductor memory that stores bits in bistable circuits without periodic refresh. It is faster but less dense and more expensive than DRAM, suiting caches.
Memory protection: Hardware and software mechanisms that restrict which processes can access particular memory regions. It prevents programs from corrupting each other's data or system code.
Cache memory: Small, fast memory that keeps copies of data likely to be used soon by a processor. It bridges the speed gap between processor execution and larger memory.
Cache coherence: Protocols and rules that keep cached copies of shared data consistent across processors. Multiple caches can hold copies of the same memory location.

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