In information processing, a state is the complete set of properties (for example, its energy level, etc. see state (physics)) transmitted by an object to an observer via one or more channels. Any change in the nature or quantity of such properties in a state is detected by an observer and thus a transmission of information occurs. In general, information processing is the changing (processing) of information in any manner detectable by an observer. ... In mathematics, a set can be thought of as any collection of distinct things considered as a whole. ... A property is an intrinsic or extrinsic quality of an object—where an object may be of any differing nature, depending on the context and field — be it computing, philosophy, etc. ... A quantum mechanical system can only be in certain states, so that only certain energy levels are possible. ... In physics, the term state is used in several related senses, each of which expresses something about the way a physical system is. ... WordNet gives four main senses for the English noun object: a physical entity; something that is within the grasp of the senses; an aim, target or objective — see Object (task); a grammatical Object — either a direct object or an indirect object the focus of cognitions or feelings. ... Possible meanings: In general, an observer is any system which receives information from an object. ... Channel, in communications (sometimes called communications channel), refers to the medium through which information is transmitted from a sender (or transmitter) to a receiver. ... Information is a word which has many different meanings in everyday usage and in specialized contexts, but as a rule, the concept is closely related to others such as data, instruction, knowledge, meaning, communication, representation, and mental stimulus. ...

In computer science, state is a concept in automata theory which occasionally extends into some forms of systems programming such as lexers and parsers. Wikibooks Wikiversity has more about this subject: School of Computer Science Open Directory Project: Computer Science Downloadable Science and Computer Science books Collection of Computer Science Bibliographies Belief that title science in computer science is inappropriate Categories: ‪Wikipedia articles needing priority cleanup‬ | ‪Computer science‬ ... Automata theory is a field of computer science which studies finite state machines, by means of mathematical representations of them (automata, Turing machines). ... System programming (or systems programming) is the activity of building and maintaining, low-level, system software for computers, including operating systems, system utilities, compilers, and so forth. ... Lexical analysis is the process of taking an input string of characters (such as the source code of a computer program) and producing a sequence of symbols called lexical tokens, or just tokens, which may be handled more easily by a parser. ... A parser is a computer program or a component of a program that analyses the grammatical structure of an input, with respect to a given formal grammar, a process known as parsing. ...

Whether the automaton in question is a finite state machine, a pushdown automaton or a full-fledged Turing machine, a state is a particular set of instructions which will be executed in response to the machine's input. The state can be thought of as analogous to a practical computer's main memory. The behavior of the system is a function of (a) the definition of the automaton, (b) the input and (c) the current state. It has been suggested that this article or section be merged with Deterministic finite state machine. ... In automata theory, pushdown automata (PDA) are abstract devices that recognize context-free languages. ... An artistic representation of a Turing Machine . ...

An information system or protocol that relies upon state is said to be stateful. One that does not is said to be stateless. For example, there are stateless firewalls and stateless servers, and HTTP is considered a stateless protocol. A character encoding such as ISO 2022 is said to be stateful if the interpretation of a particular code value depends on the code values that came before it. The term information system has the following meanings: 1. ... The word protocol derives from a Greek phrase meaning first leaf, referring to the first draft of a treaty. ... In computing, a stateless firewall is a firewall that treats each network frame (or packet) in isolation. ... A stateless server is one that treats each request as an independent transaction, unrelated to any previous request. ... HTTP (for HyperText Transfer Protocol) is the primary method used to convey information on the World Wide Web. ... A character encoding consists of a code that pairs a set of characters (representations of graphemes or grapheme-like units, such as might appear in an alphabet or syllabary for the communication of a natural language) with a set of something else, such as numbers or electrical pulses, in order... ISO 2022, more formally ISO/IEC 2022, is an ISO standard (equivalent to the ECMA standard ECMA-35) specifying a technique for including multiple character sets in a single character encoding. ...

See also

• Clumping
• State diagram
• program state