Puskurilähde

Puskurilähde, also known as a buffer pool, is a memory management technique used in computer systems. It is a dedicated area of RAM that temporarily stores data being read from or written to a storage device, such as a hard disk drive or solid-state drive. The primary purpose of a puskurilähde is to bridge the speed difference between the much faster central processing unit (CPU) and the slower I/O devices.

When data is read from a storage device, it is first brought into the puskurilähde. If the CPU needs this data again soon, it can be accessed directly from the puskurilähde, which is significantly faster than reading it from the storage device again. This reduces latency and improves overall system performance. Similarly, when data is written, it is often first written to the puskurilähde. The system can then inform the application that the write operation is complete, while the actual writing to the slower storage device occurs in the background. This allows the CPU to continue with other tasks without waiting for the I/O operation to finish.

The size of the puskurilähde is a critical factor in its effectiveness. A larger puskurilähde can hold more data, increasing the chances of a cache hit (finding requested data already in the buffer). However, excessively large buffers can consume valuable system memory. Operating systems and applications employ various algorithms to manage the puskurilähde efficiently, deciding which data to keep and which to evict when new data needs to be stored. Common eviction policies include least recently used (LRU) and first-in, first-out (FIFO).