Cache (computing)In computing, a cache (kæʃ ) is a hardware or software component that stores data so that future requests for that data can be served faster; the data stored in a cache might be the result of an earlier computation or a copy of data stored elsewhere. A cache hit occurs when the requested data can be found in a cache, while a cache miss occurs when it cannot. Cache hits are served by reading data from the cache, which is faster than recomputing a result or reading from a slower data store; thus, the more requests that can be served from the cache, the faster the system performs.
Web cacheA Web cache (or HTTP cache) is a system for optimizing the World Wide Web. It is implemented both client-side and server-side. The caching of multimedia and other can result in less overall delay when browsing the Web. A forward cache is a cache outside the web server's network, e.g. in the client's web browser, in an ISP, or within a corporate network. A network-aware forward cache only caches heavily accessed items. A proxy server sitting between the client and web server can evaluate HTTP headers and choose whether to store web content.
CPU cacheA CPU cache is a hardware cache used by the central processing unit (CPU) of a computer to reduce the average cost (time or energy) to access data from the main memory. A cache is a smaller, faster memory, located closer to a processor core, which stores copies of the data from frequently used main memory locations. Most CPUs have a hierarchy of multiple cache levels (L1, L2, often L3, and rarely even L4), with different instruction-specific and data-specific caches at level 1.
Request for quotationA request for quotation (RfQ) is a business process in which a company or public entity requests a quote from a supplier for the purchase of specific products or services. RfQ generally means the same thing as Call for bids (CfB) and Invitation for bid (IfB). An RfQ typically involves more than the price per item. Information like payment terms, quality level per item or contract length may be requested during the bidding process.
File systemIn computing, a file system or filesystem (often abbreviated to fs) is a method and data structure that the operating system uses to control how data is stored and retrieved. Without a file system, data placed in a storage medium would be one large body of data with no way to tell where one piece of data stopped and the next began, or where any piece of data was located when it was time to retrieve it. By separating the data into pieces and giving each piece a name, the data are easily isolated and identified.
Kernel (operating system)The kernel is a computer program at the core of a computer's operating system and generally has complete control over everything in the system. It is the portion of the operating system code that is always resident in memory and facilitates interactions between hardware and software components. A full kernel controls all hardware resources (e.g. I/O, memory, cryptography) via device drivers, arbitrates conflicts between processes concerning such resources, and optimizes the utilization of common resources e.
World Wide WebThe World Wide Web (WWW), commonly known as the Web, is an information system enabling information to be shared over the Internet through simplified ways meant to appeal to users beyond IT specialists and hobbyists, as well as documents and other web resources to be accessed over the Internet according to specific rules, the Hypertext Transfer Protocol (HTTP). Documents and downloadable media are made available to the network through web servers and can be accessed by programs such as web browsers.
Page cacheIn computing, a page cache, sometimes also called disk cache, is a transparent cache for the pages originating from a secondary storage device such as a hard disk drive (HDD) or a solid-state drive (SSD). The operating system keeps a page cache in otherwise unused portions of the main memory (RAM), resulting in quicker access to the contents of cached pages and overall performance improvements. A page cache is implemented in kernels with the paging memory management, and is mostly transparent to applications.
Distributed hash tableA distributed hash table (DHT) is a distributed system that provides a lookup service similar to a hash table. Key–value pairs are stored in a DHT, and any participating node can efficiently retrieve the value associated with a given key. The main advantage of a DHT is that nodes can be added or removed with minimum work around re-distributing keys. Keys are unique identifiers which map to particular values, which in turn can be anything from addresses, to documents, to arbitrary data.
HTTPThe Hypertext Transfer Protocol (HTTP) is an application layer protocol in the Internet protocol suite model for distributed, collaborative, hypermedia information systems. HTTP is the foundation of data communication for the World Wide Web, where hypertext documents include hyperlinks to other resources that the user can easily access, for example by a mouse click or by tapping the screen in a web browser. Development of HTTP was initiated by Tim Berners-Lee at CERN in 1989 and summarized in a simple document describing the behavior of a client and a server using the first HTTP version, named 0.
