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EAccelerator
eAccelerator is a PHP accelerator derived from the MMCache extension for the PHP programming language. eAccelerator provides a bytecode cache. eAccelerator is open source and thereby free to use and distribute. Old and unmaintained versions also provided an encoder. Every time a PHP script is accessed, PHP usually parses and compiles scripts to bytecode. Once installed, eAccelerator optimizes the compiled bytecode and caches this to shared memory or disk or both. Upon subsequent accesses to a script, eAccelerator will access cached bytecode if it is available instead of the script being compiled. This avoids the performance overhead of repeated parsing and compilation. Previous eAccelerator versions also provided functions for use in PHP scripts that allow access to shared memory, automatic web (content) caching, and other related tasks. These were removed as of version 0.9.6rc1. Old eAccelerator versions had an encoder component that creates a file that cannot be as easily read ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alternative PHP Cache
This is a list of PHP accelerators. Alternative PHP Cache (APC) Alternative PHP Cache is a free and open (PHP license) framework that caches the output of the PHP bytecode compiler in shared memory, thus reducing parsing and disk I/O overhead for later requests; and a shared memory cache for user data. For an application consisting of a large source code base such as Drupal, a 3x increase in page generation speed is possible as a result. It has been used at Facebook and has a mature codebase thanks to numerous contributors, including Facebook itself. APC was originally scheduled for inclusion into the PHP core no later than PHP 6. While multiple accelerator projects were considered desirable, the focus has since moved to Optimizer Plus, and, later, Zend Opcache that is included in the core distribution as of PHP 5.5. Since March 2013, a beta version of APCu (APC User Cache) is available, in which all opcode caching abilities have been removed to support user caches in shared m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
MMCache
MMCache, also known as Turck MMCache, is a PHP accelerator, or an extension to PHP meant to improve performance. It is structured as a simple proxy server between the web server and the web browser. Its most important feature is using memcached for caching the data in memory. MMCache is free software released under the GNU GPL 2.0. The key identifying the given site is designated from the URL, so if, for example, there is a session defined within the URL, then the proxy will not work effectively. A newer version of MMCache, MMCache-LB, has an option to connect more web servers behind the proxy, with load balancing between them. Development work on MMCache was discontinued in 2009, and the code was forked into the eAccelerator application. See also * List of PHP accelerators * Web caching * Zend Performance Suite The Zend Engine is a compiler and runtime environment for the PHP scripting language and consists of the Zend Virtual Machine, which is composed of the Zend Compil ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
PHP Accelerator
A PHP accelerator is a PHP extension designed to improve the performance of software applications written in the PHP programming language. Operation Most PHP accelerators work by caching the compiled opcode/bytecode of PHP representation of php files to avoid the overhead of parsing and compiling source code on each request (some or even most of which may never be executed). To further improve performance, the cached code is stored in shared memory and directly executed from there, minimizing the amount of slow disk reads and memory copying at runtime. Practical benefits PHP accelerators substantially increase the speed of PHP applications. Improvements of web page generation throughput by factors of two to seven have been observed. The effect on application performance of opcode caching varies widely, depending on factors such as the inherent execution time of the PHP application and the percentage of source code actually executed on a given request, and whether additional ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fork (software)
In software engineering, a project fork happens when developers take a copy of source code from one software package and start independent development on it, creating a distinct and separate piece of software. The term often implies not merely a development branch, but also a split in the developer community; as such, it is a form of schism. Grounds for forking are varying user preferences and stagnated or discontinued development of the original software. Free and open-source software is that which, by definition, may be forked from the original development team without prior permission, and without violating copyright law. However, licensed forks of proprietary software (''e.g.'' Unix) also happen. Etymology The word "fork" has been used to mean "to divide in branches, go separate ways" as early as the 14th century. In the software environment, the word evokes the fork system call, which causes a running process to split itself into two (almost) identical copies that (ty ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Software Extension
In computing, a plug-in (or plugin, add-in, addin, add-on, or addon) is a software component that adds a specific feature to an existing computer program. When a program supports plug-ins, it enables customization. A theme or skin is a preset package containing additional or changed graphical appearance details, achieved by the use of a graphical user interface (GUI) that can be applied to specific software and websites to suit the purpose, topic, or tastes of different users to customize the look and feel of a piece of computer software or an operating system front-end GUI (and window managers). Purpose and examples Applications may support plug-ins to: * enable third-party developers to extend an application * support easily adding new features * reduce the size of an application by not loading unused features * separate source code from an application because of incompatible software licenses. Types of applications and why they use plug-ins: * Digital audio workstations an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Programming Language
A programming language is a system of notation for writing computer programs. Most programming languages are text-based formal languages, but they may also be graphical. They are a kind of computer language. The description of a programming language is usually split into the two components of syntax (form) and semantics (meaning), which are usually defined by a formal language. Some languages are defined by a specification document (for example, the C programming language is specified by an ISO Standard) while other languages (such as Perl) have a dominant implementation that is treated as a reference. Some languages have both, with the basic language defined by a standard and extensions taken from the dominant implementation being common. Programming language theory is the subfield of computer science that studies the design, implementation, analysis, characterization, and classification of programming languages. Definitions There are many considerations when defini ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bytecode
Bytecode (also called portable code or p-code) is a form of instruction set designed for efficient execution by a software interpreter. Unlike human-readable source code, bytecodes are compact numeric codes, constants, and references (normally numeric addresses) that encode the result of compiler parsing and performing semantic analysis of things like type, scope, and nesting depths of program objects. The name bytecode stems from instruction sets that have one-byte opcodes followed by optional parameters. Intermediate representations such as bytecode may be output by programming language implementations to ease interpretation, or it may be used to reduce hardware and operating system dependence by allowing the same code to run cross-platform, on different devices. Bytecode may often be either directly executed on a virtual machine (a p-code machine, i.e., interpreter), or it may be further compiled into machine code for better performance. Since bytecode instructions ar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cache (computing)
In computing, a cache ( ) 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. To be cost-effective and to enable efficient use of data, caches must be relatively small. Nevertheless, caches have proven themselves in many areas of computing, because typical computer applications access data with a high degree of locality of reference. Such access patterns exhibit temporal locality, where data is requested that has been recently requested already, and spatial locality, where d ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Open-source License
An open-source license is a type of license for computer software and other products that allows the source code, blueprint or design to be used, modified and/or shared under defined terms and conditions. This allows end users and commercial companies to review and modify the source code, blueprint or design for their own customization, curiosity or troubleshooting needs. Open-source licensed software is mostly available free of charge, though this does not necessarily have to be the case. Licenses which only permit non-commercial redistribution or modification of the source code for personal use only are generally not considered as open-source licenses. However, open-source licenses may have some restrictions, particularly regarding the expression of respect to the origin of software, such as a requirement to preserve the name of the authors and a copyright statement within the code, or a requirement to redistribute the licensed software only under the same license (as in a copy ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Shared Memory (interprocess Communication)
In computer science, shared memory is memory that may be simultaneously accessed by multiple programs with an intent to provide communication among them or avoid redundant copies. Shared memory is an efficient means of passing data between programs. Depending on context, programs may run on a single processor or on multiple separate processors. Using memory for communication inside a single program, e.g. among its multiple threads, is also referred to as shared memory. In hardware In computer hardware, ''shared memory'' refers to a (typically large) block of random access memory (RAM) that can be accessed by several different central processing units (CPUs) in a multiprocessor computer system. Shared memory systems may use: * uniform memory access (UMA): all the processors share the physical memory uniformly; * non-uniform memory access (NUMA): memory access time depends on the memory location relative to a processor; * cache-only memory architecture (COMA): the local memor ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Web Caching
A 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 multimedias and other files can result in less overall delay when browsing the Web. Parts of the system Forward and reverse 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. A reverse cache sits in front of one or more web servers, accelerating requests from the Internet and reducing peak server load. This is usually a content delivery network (CDN) that retains copies of web content at various points throughout a network. HTTP options The Hypertext Transfer Protocol (HTTP) defines three basic mechanisms for controlling caches: freshness, validation, and invalidatio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Free Software
Free software or libre software is computer software distributed under terms that allow users to run the software for any purpose as well as to study, change, and distribute it and any adapted versions. Free software is a matter of liberty, not price; all users are legally free to do what they want with their copies of a free software (including profiting from them) regardless of how much is paid to obtain the program.Selling Free Software (gnu.org) Computer programs are deemed "free" if they give end-users (not just the developer) ultimate control over the software and, subsequently, over their devices. The right to study and modify a computer program entails that |
