# disk cache

> any component used to cache data that permanently resides on a computer drive

**Wikidata**: [Q5282303](https://www.wikidata.org/wiki/Q5282303)  
**Wikipedia**: [English](https://en.wikipedia.org/wiki/Disk_cache)  
**Source**: https://4ort.xyz/entity/disk-cache

## Summary
A disk cache is any component used to cache data that permanently resides on a computer drive. It serves to increase data transfer rates and reduce latency by transparently storing data so that future requests can be served faster. It is also known by the alias "drive cache."

## Key Facts
*   **Definition:** Any component used to cache data that permanently resides on a computer drive.
*   **Primary Function:** Used to increase data transfer rates and achieve a reduction in latency.
*   **Parent Class:** Subclass of "cache" (a computing component that transparently stores data).
*   **Alias:** Also referred to as "drive cache."
*   **Related Component (Disk Buffer):** Associated with the "disk buffer," a high-speed memory embedded directly in a computer drive to improve performance.
*   **Related Component (Page Cache):** Associated with the "page cache," a software-based, block-level cache stored in the host computer's main memory.
*   **Wikipedia Presence:** Maintains entries in English (en) and Korean (ko).

## FAQs
### Q: What is the primary purpose of a disk cache?
A: The primary purpose of a disk cache is to increase the data transfer rate and reduce latency. It achieves this by storing data temporarily to serve future requests faster than retrieving it directly from the permanent drive.

### Q: How does a disk cache relate to a disk buffer?
A: While both improve performance, a disk buffer is specifically defined as high-speed memory embedded directly within a computer drive. A disk cache acts as a broader category or related component for caching drive data.

### Q: Is a disk cache a hardware or software component?
A: The term "disk cache" is a broad classification. It encompasses hardware solutions like the embedded "disk buffer" as well as software solutions like the "page cache," which resides in the host computer's main memory.

## Why It Matters
Disk cache plays a critical role in computing performance by bridging the speed gap between fast computer processors and slower permanent storage drives. Without a caching mechanism, every data request would require access to the physical drive, resulting in significant delays and lower system responsiveness. By transparently storing frequently accessed data in faster memory components—whether in the host's main memory (page cache) or the drive's embedded memory (disk buffer)—disk caching drastically reduces latency and increases data transfer rates. This process is fundamental to modern computing, ensuring that operating systems and applications load quickly and operate smoothly.

## Notable For
*   **Broad Classification:** Distinct from specific hardware buffers because it encompasses "any component" used for the caching purpose.
*   **Performance Optimization:** Specifically targets the "increase" of data transfer rates and the "reduction" of latency.
*   **Transparency:** Operates as a "transparent" storage mechanism, meaning it functions without the explicit knowledge or intervention of the user or requesting process.
*   **Dual Implementation:** Uniquely defined by its relationship to both hardware (disk buffer) and software (page cache) implementations.

## Body

### Definition and Classification
A disk cache is defined as any component used to cache data that permanently resides on a computer drive. It is classified as a specific type of **cache**, which is broadly a computing component that transparently stores data to serve future requests faster. The entity holds a "sitelink count" of 2 and is active in English and Korean language Wikipedia entries.

### Operational Utility
The technical utility of a disk cache is strictly defined by two criteria found in structured property data:
1.  **Increase:** It is used to increase the value of the "data transfer rate."
2.  **Reduction:** It is used to effect a reduction in "latency."

### Relationship to Other Components
In the hierarchy of computing components, the disk cache is closely related to two other classes of items:
*   **Disk Buffer:** A "disk buffer" is a form of high-speed memory embedded directly into a computer drive. While similar in goal, the disk cache is the broader functional concept, whereas the disk buffer is a specific hardware implementation.
*   **Page Cache:** This is a software-based, block-level cache of drive data stored specifically in the host computer's main memory. This distinguishes it from hardware-only solutions embedded in the drive itself.