|
Concurrency Patterns
In software engineering, concurrency patterns are those types of design patterns that deal with the multi-threaded programming paradigm. Examples of this class of patterns include: * Active object * Balking pattern * Barrier * Double-checked locking * Guarded suspension * Leaders/followers pattern * Monitor object * Nuclear reaction * Reactor pattern * Readers–writer lock * Scheduler pattern * Thread pool pattern * Thread-local storage See also * '' Design Patterns'' (book) * Behavioral pattern * Creational pattern In software engineering, creational design patterns are design patterns that deal with object creation Object may refer to: General meanings * Object (philosophy), a thing, being, or concept ** Object (abstract), an object which does not ex ... * Structural pattern References External links ScaleConf Presentation about concurrency patternsGopherCon Rethinking Classical Concurrency Patterns [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Software Engineering
Software engineering is a branch of both computer science and engineering focused on designing, developing, testing, and maintaining Application software, software applications. It involves applying engineering design process, engineering principles and computer programming expertise to develop software systems that meet user needs. The terms ''programmer'' and ''coder'' overlap ''software engineer'', but they imply only the construction aspect of a typical software engineer workload. A software engineer applies a software development process, which involves defining, Implementation, implementing, Software testing, testing, Project management, managing, and Software maintenance, maintaining software systems, as well as developing the software development process itself. History Beginning in the 1960s, software engineering was recognized as a separate field of engineering. The development of software engineering was seen as a struggle. Problems included software that was over ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Readers–writer Lock
In computer science, a readers–writer (single-writer lock, a multi-reader lock, a push lock, or an MRSW lock) is a synchronization primitive that solves one of the readers–writers problems. An RW lock allows concurrent access for read-only operations, whereas write operations require exclusive access. This means that multiple threads can read the data in parallel but an exclusive lock is needed for writing or modifying data. When a writer is writing the data, all other writers and readers will be blocked until the writer is finished writing. A common use might be to control access to a data structure in memory that cannot be updated atomically and is invalid (and should not be read by another thread) until the update is complete. Readers–writer locks are usually constructed on top of mutexes and condition variables, or on top of semaphores. Upgradable RW lock Some RW locks allow the lock to be atomically upgraded from being locked in read-mode to write-mode, as well ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Concurrent Computing
Concurrent computing is a form of computing in which several computations are executed '' concurrently''—during overlapping time periods—instead of ''sequentially—''with one completing before the next starts. This is a property of a system—whether a program, computer, or a network—where there is a separate execution point or "thread of control" for each process. A ''concurrent system'' is one where a computation can advance without waiting for all other computations to complete. Concurrent computing is a form of modular programming. In its paradigm an overall computation is factored into subcomputations that may be executed concurrently. Pioneers in the field of concurrent computing include Edsger Dijkstra, Per Brinch Hansen, and C.A.R. Hoare. Introduction The concept of concurrent computing is frequently confused with the related but distinct concept of parallel computing, Pike, Rob (2012-01-11). "Concurrency is not Parallelism". ''Waza conference'', 11 Ja ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sound Recording And Reproduction
Sound recording and reproduction is the electrical, Mechanical system, mechanical, electronic, or digital inscription and re-creation of sound waves, such as spoken voice, singing, instrumental music, or sound effects. The two main classes of sound recording technology are analog recording and digital recording. Acoustic analog recording is achieved by a microphone diaphragm that senses changes in atmospheric pressure caused by acoustics, acoustic sound waves and records them as a mechanical representation of the sound waves on a medium such as a phonograph record (in which a stylus cuts grooves on a record). In magnetic tape recording, the sound waves vibrate the microphone diaphragm and are converted into a varying electric current, which is then converted to a varying magnetic field by an electromagnet, which makes a representation of the sound as magnetized areas on a plastic tape with a magnetic coating on it. Analog sound reproduction is the reverse process, with a large ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Structural Pattern
In software engineering, structural design patterns are design patterns that ease the design by identifying a simple way to realize relationships among entities. Examples of Structural Patterns include: * Adapter pattern: 'adapts' one interface for a class into one that a client expects ** Adapter pipeline: Use multiple adapters for debugging purposes. ** Retrofit Interface Pattern: An adapter used as a new interface for multiple classes at the same time. * Aggregate pattern: a version of the Composite pattern with methods for aggregation of children * Bridge pattern: decouple an abstraction from its implementation so that the two can vary independently ** Tombstone: An intermediate "lookup" object contains the real location of an object. * Composite pattern: a tree structure of objects where every object has the same interface * Decorator pattern: add additional functionality to an object at runtime where subclassing would result in an exponential rise of new classes * Extensibil ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Creational Pattern
In software engineering, creational design patterns are design patterns that deal with object creation Object may refer to: General meanings * Object (philosophy), a thing, being, or concept ** Object (abstract), an object which does not exist at any particular time or place ** Physical object, an identifiable collection of matter * Goal, an a ... mechanisms, trying to create objects in a manner suitable to the situation. The basic form of object creation could result in design problems or in added complexity to the design due to inflexibility in the creation procedures. Creational design patterns solve this problem by somehow controlling this object creation. Overview Creational design patterns are composed of two dominant ideas. One is encapsulating knowledge about which concrete classes the system uses. Another is hiding how instances of these concrete classes are created and combined. Creational design patterns are further categorized into object-creational patterns ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Behavioral Pattern
In software engineering, behavioral design patterns are design patterns that identify common communication patterns among objects. By doing so, these patterns increase flexibility in carrying out communication. Design patterns Examples of this type of design pattern include: ; Blackboard design pattern : Provides a computational framework for the design and implementation of systems that integrate large and diverse specialized modules, and implement complex, non-deterministic control strategies ; Chain-of-responsibility pattern : Command objects are handled or passed on to other objects by logic-containing processing objects ;Command pattern : Command objects encapsulate an action and its parameters ;"Externalize the stack" : Turn a recursive function into an iterative function that uses a stack ; Interpreter pattern : Implement a specialized computer language to rapidly solve a specific set of problems ; Iterator pattern : Iterators are used to access the elements of an aggreg ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Design Patterns
''Design Patterns: Elements of Reusable Object-Oriented Software'' (1994) is a software engineering book describing software design patterns. The book was written by Erich Gamma, Richard Helm, Ralph Johnson, and John Vlissides, with a foreword by Grady Booch. The book is divided into two parts, with the first two chapters exploring the capabilities and pitfalls of object-oriented programming, and the remaining chapters describing 23 classic software design patterns. The book includes examples in C++ and Smalltalk. It has been influential to the field of software engineering and is regarded as an important source for object-oriented design theory and practice. More than 500,000 copies have been sold in English and in 13 other languages. The authors are often referred to as the ''Gang of Four'' (GoF). Development and publication history The book started at a birds-of-a-feather session at the 1990 OOPSLA meeting, "Towards an Architecture Handbook", where Erich Gamma and Ri ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thread-local Storage
In computer programming, thread-local storage (TLS) is a memory management method that uses static memory allocation, static or global computer storage, memory local to a thread (computing), thread. The concept allows storage of data that appears to be global in a system with separate threads. Many systems impose restrictions on the size of the thread-local memory block, in fact often rather tight limits. On the other hand, if a system can provide at least a memory address (pointer) sized variable thread-local, then this allows the use of arbitrarily sized memory blocks in a thread-local manner, by allocating such a memory block dynamically and storing the memory address of that block in the thread-local variable. On reduced instruction set computer, RISC machines, the calling convention often reserves a thread pointer register for this use. Usage While the use of global variables is generally discouraged in modern programming, some older operating systems such as UNIX were orig ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thread Pool Pattern
In computer programming, a thread pool is a software design pattern for achieving concurrency of execution in a computer program. Often also called a replicated workers or worker-crew model, a thread pool maintains multiple threads waiting for tasks to be allocated for concurrent execution by the supervising program. By maintaining a pool of threads, the model increases performance and avoids latency in execution due to frequent creation and destruction of threads for short-lived tasks. Another good property - the ability to limit system load, when we use fewer threads than available. The number of available threads is tuned to the computing resources available to the program, such as a parallel task queue after completion of execution. Performance The size of a thread pool is the number of threads kept in reserve for executing tasks. It is usually a tunable parameter of the application, adjusted to optimize program performance. Deciding the optimal thread pool size is crucia ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Scheduler Pattern
In computing, scheduling is the action of assigning resources to perform tasks. The resources may be processors, network links or expansion cards. The tasks may be threads, processes or data flows. The scheduling activity is carried out by a mechanism called a scheduler. Schedulers are often designed so as to keep all computer resources busy (as in load balancing), allow multiple users to share system resources effectively, or to achieve a target quality-of-service. Scheduling is fundamental to computation itself, and an intrinsic part of the execution model of a computer system; the concept of scheduling makes it possible to have computer multitasking with a single central processing unit (CPU). Goals A scheduler may aim at one or more goals, for example: * maximizing ''throughput'' (the total amount of work completed per time unit); * minimizing '' wait time'' (time from work becoming ready until the first point it begins execution); * minimizing '' latency'' or '' r ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Reactor Pattern
The reactor software design pattern is an event handling strategy that can respond to many potential service requests concurrently. The pattern's key component is an event loop, running in a ''single'' thread or process, which demultiplexes incoming requests and dispatches them to the correct request handler. By relying on event-based mechanisms rather than blocking I/O or multi-threading, a reactor can handle many concurrent I/O bound requests with minimal delay. A reactor also allows for easily modifying or expanding specific request handler routines, though the pattern does have some drawbacks and limitations. With its balance of simplicity and scalability, the reactor has become a central architectural element in several server applications and software frameworks for networking. Derivations such as the multireactor and proactor also exist for special cases where even greater throughput, performance, or request complexity are necessary. Overview Practical considerati ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
