speichercache

Speichercache is a term used to describe a cache memory that stores copies of data from slower storage to accelerate data access in computer systems. It can refer to both hardware caches within processors and software caches managed by an operating system. The primary purpose of a speichercache is to reduce average memory latency and increase throughput by exploiting temporal and spatial locality in data access patterns.

In hardware, the most prominent example is the CPU cache. These caches are small, fast memory (typically SRAM) located close to the processor and organized into multiple levels, such as L1, L2, and L3. L1 caches are the fastest and smallest, while higher levels are larger but slower and often shared among cores. Data moves between cache levels and main memory in fixed cache lines. Cache mapping policies determine where data can be stored, with direct-mapped, set-associative, and fully associative configurations commonly used. Cache coherence protocols, such as MESI, ensure that multiple cores maintain a consistent view of cached data. Write policies vary, including write-through and write-back.

In software, speichercache also encompasses the page cache or file system cache managed by the operating system. This cache holds recently accessed disk blocks in RAM to speed up file I/O and reduce disk activity. Cache behavior is typically transparent to applications, though APIs and kernel parameters can influence size and eviction strategies.

Key performance metrics include cache hit rate, miss penalty, and cache size. Misses are categorized as compulsory, conflict, or capacity, which informs optimization decisions. Designers balance cache size, speed, energy use, and hardware cost to improve overall system performance.

See also: CPU cache, memory hierarchy, cache coherence, disk cache, page cache, caching algorithms.