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Computer Science
Computer science is the study of computation, information, and automation. Computer science spans Theoretical computer science, theoretical disciplines (such as algorithms, theory of computation, and information theory) to Applied science, applied disciplines (including the design and implementation of Computer architecture, hardware and Software engineering, software). Algorithms and data structures are central to computer science. The theory of computation concerns abstract models of computation and general classes of computational problem, problems that can be solved using them. The fields of cryptography and computer security involve studying the means for secure communication and preventing security vulnerabilities. Computer graphics (computer science), Computer graphics and computational geometry address the generation of images. Programming language theory considers different ways to describe computational processes, and database theory concerns the management of re ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Scheduling Algorithm
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 '' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Acronym
An acronym is a type of abbreviation consisting of a phrase whose only pronounced elements are the initial letters or initial sounds of words inside that phrase. Acronyms are often spelled with the initial Letter (alphabet), letter of each word in all caps with no punctuation. For some, an initialism or alphabetism connotes this general meaning, and an ''acronym'' is a subset with a narrower definition; an acronym is pronounced as a word rather than as a sequence of letters. In this sense, ''NASA'' () is an acronym, but ''United States, USA'' () is not. The broader sense of ''acronym'', ignoring pronunciation, is its original meaning and in common use. . Dictionary and style-guide editors dispute whether the term ''acronym'' can be legitimately applied to abbreviations which are not pronounced as words, and they do not agree on acronym space (punctuation), spacing, letter case, casing, and punctuation. The phrase that the acronym stands for is called its . The of an acron ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
FIFO (computing And Electronics)
Representation of a FIFO queue In computing and in systems theory, first in, first out (the first in is the first out), acronymized as FIFO, is a method for organizing the manipulation of a data structure (often, specifically a data buffer) where the oldest (first) entry, or "head" of the queue, is processed first. Such processing is analogous to servicing people in a queue area on a first-come, first-served (FCFS) basis, i.e. in the same sequence in which they arrive at the queue's tail. FCFS is also the jargon term for the FIFO operating system scheduling algorithm, which gives every process central processing unit (CPU) time in the order in which it is demanded. FIFO's opposite is LIFO, last-in-first-out, where the youngest entry or "top of the stack" is processed first. A priority queue is neither FIFO or LIFO but may adopt similar behaviour temporarily or by default. Queueing theory encompasses these methods for processing data structures, as well as interactions be ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
LIFO (computing)
In computer science, a stack is an abstract data type that serves as a collection of elements with two main operations: * Push, which adds an element to the collection, and * Pop, which removes the most recently added element. Additionally, a peek operation can, without modifying the stack, return the value of the last element added. The name ''stack'' is an analogy to a set of physical items stacked one atop another, such as a stack of plates. The order in which an element added to or removed from a stack is described as last in, first out, referred to by the acronym LIFO. As with a stack of physical objects, this structure makes it easy to take an item off the top of the stack, but accessing a datum deeper in the stack may require removing multiple other items first. Considered a sequential collection, a stack has one end which is the only position at which the push and pop operations may occur, the ''top'' of the stack, and is fixed at the other end, the ''bottom''. A s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
State (computer Science)
In information technology and computer science, a system is described as stateful if it is designed to remember preceding events or user interactions; the remembered information is called the state of the system. The set of states a system can occupy is known as its state space. In a discrete system, the state space is countable and often finite. The system's internal behaviour or interaction with its environment consists of separately occurring individual actions or events, such as accepting input or producing output, that may or may not cause the system to change its state. Examples of such systems are digital logic circuits and components, automata and formal language, computer programs, and computers. The output of a digital circuit or deterministic computer program at any time is completely determined by its current inputs and its state. Digital logic circuit state Digital logic circuits can be divided into two types: combinational logic, whose output signals a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Memory Leak
In computer science, a memory leak is a type of resource leak that occurs when a computer program incorrectly manages memory allocations in a way that memory which is no longer needed is not released. A memory leak may also happen when an object is stored in memory but cannot be accessed by the running code (i.e. unreachable memory). A memory leak has symptoms similar to a number of other problems and generally can only be diagnosed by a programmer with access to the program's source code. A related concept is the "space leak", which is when a program consumes excessive memory but does eventually release it. Because they can exhaust available system memory as an application runs, memory leaks are often the cause of or a contributing factor to software aging. Effects Minor leaks If a program has a memory leak and its memory usage is steadily increasing, there will not usually be an immediate symptom. In modern operating systems, normal memory used by an application is releas ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Signetics
Signetics Corporation was an American electronics manufacturer specifically established to make integrated circuits. Founded in 1961, they went on to develop a number of early microprocessors and support chips, as well as the widely used 555 timer IC, 555 timer chip. The company was bought by Philips in 1975 and incorporated in NXP Semiconductors, Philips Semiconductors (now NXP). History Signetics was started in 1961, by a group of engineers (David Allison, David James, Lionel Kattner, and Mark Weissenstern) who had left Fairchild Semiconductor. At the time, Fairchild was concentrating on its discrete component business (mostly transistors), and its management felt that by making integrated circuits (ICs) it would lose its customers. Signetics founders believed that ICs were the future of electronics (much like another contemporary Fairchild spinoff, Amelco) and wished to commercialize them. The name of the new company was coined from Signal Network Electronics. The venture was ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Write-only Memory (joke)
Write-only memory (WOM), the opposite of read-only memory (ROM), began as a humorous reference to a memory device that could be written to but not read, as there seemed to be no practical use for a memory circuit from which data could not be retrieved. However, it was eventually recognized that write-only memory also describes certain functionalities in microprocessor systems. The concept is still often used as a joke or euphemism for a failed memory device. The first use of the term is generally attributed to Signetics, whose ''write-only memory'' literature, created in 1972 as in-house practical joke, is frequently referenced within the electronics industry,. a staple of software engineering lexicons, and included in "best hoaxes" collections. Signetics A "Write-Only Memory" datasheet was created "as a lark" by Signetics engineer John G "Jack" Curtis,. inspired by a fictitious and humorous vacuum tube datasheet from the 1940s. Considered "an icebreaker", it was deliberately inc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bit Bucket
In computing jargon, the bit bucket (or byte bucket) is where lost computerized data has gone, by any means; any data which does not end up where it is supposed to, being lost in transmission, a computer crash, or the like, is said to have gone to the bit bucket – that mysterious place on a computer where lost data goes, as in: History Originally, the bit bucket was the container on teletype machines or IBM key punch machines into which chad from the paper tape punch or card punch was deposited; the formal name is "chad box" or (at IBM) " chip box". The term was then generalized into any place where useless bits go, a useful computing concept known as the null device. The term bit bucket is also used in discussions of bit shift operations. The bit bucket is related to the first in never out buffer and write-only memory, in a joke datasheet issued by Signetics in 1972. In a 1988 April Fool's article in ''Compute!'' magazine, Atari BASIC author Bill Wilkinson prese ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Black Hole (networking)
In networking, a black hole refers to a place in the network where incoming or outgoing traffic is discarded (or "dropped" or sinkholed) without informing the source that the data did not reach its intended recipient. When examining the topology of the network, the black holes themselves are invisible, and can only be detected by monitoring the lost traffic. The name is presumed to have originated from a concept of an astronomical location, a black hole. Black holes were originally defined as astronomical locations which cannot be directly observed using the definition of the holes having gravitational fields from which light cannot escape. Since 2023 with the discovery of an accretion disk of a black hole, it has been found that electromagnetic radiation produced by the disk of the black hole is available for observation by astronomy. At least since the astronomer Heber Curtis observed during 1918 visible light from a relativistic jet produced by a black hole at the centr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
/dev/null
In some operating systems, the null device is a device file that discards all data written to it but reports that the write operation succeeded. This device is called /dev/null on Unix and Unix-like systems, NUL: (see TOPS-20) or NUL on CP/M and DOS (internally \DEV\NUL), nul on OS/2 and newer Windows systems (internally \Device\Null on Windows NT), NIL: on Amiga operating systems, and NL: on OpenVMS. In Windows Powershell, the equivalent is $null. It provides no data to any process that reads from it, yielding EOF immediately. In IBM operating systems DOS/360 and successors and also in OS/360 and successors such files would be assigned in JCL to DD DUMMY. In programmer jargon, especially Unix jargon, it may also be called the bit bucket or black hole. History is described as an empty regular file in Version 4 Unix. The Version 5 Unix manual describes a device with modern semantics. Usage The null device is typically used for disposing of unwanted output streams of a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
