Disk caching is a technique used to speed up data access on computers. It involves storing frequently accessed data in a smaller, faster storage area, known as a cache, which is located closer to the processor. When the system needs data, it first checks the cache. If the data is there, it can be retrieved quickly, reducing the time it takes to access the slower hard drive or solid-state drive. This process improves overall system performance by minimizing delays. When data is not found in the cache, the system retrieves it from the main storage, and that data may also be stored in the cache for future use. This way, disk caching optimizes data retrieval and enhances user experience.