Systems and Software
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Wikipedia-Article "Systems"
A system is an assemblage of related elements comprising a whole, such that each element may be seen to be a part of that whole in some sense. That is, each element is seen to be related to other elements of and/or the whole system. It is generally recognized that while any element of a system need not have a (direct) relationship with any other particular element of a system, any element which has no relationship with any other element of a system, cannot be a part of that system.
From the Latin and Greek, the term system meant to combine, to set up, to place together.
A system typically consists of components (or elements) which interface in order to facilitate the 'flow' of information, matter or energy. The term is often used to describe a set of entities which 'act' on each other, and for which a mathematical model or a logical model may be constructed encompassing the elements and their allowed actions.
A system may be a set of rules for governing behavior or organisation. Laws are a system which governs human social behavior. Grammar is a system which governs language usage (in this case, the grammatical elements are the system elements). Cladistics is a system for classifying evolutionary relationships among living things based on derived similarity.
A sub-system is a system which is a proper subset of another system.
- For the Macintosh operating system, which was called System up to version 7.5.5, see Mac OS.
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Background
At arbritary boundaries, a collection of interrelated components may be declared a system and may further be abstracted to be declared a component of a larger system. Systems enable "activities" to be performed. (It is tempting to say that systems enable "things" to be done—but that is confusing in this context). An engineering example of a system is often a circuit or a physical series.
Depending on the type of system, a system can often be distinguished from individual machines, elements or processes of that system by the number, arrangements and complexity of those elements. For example, a pulley is a machine, but an elevator, which incorporates pulleys (amongst other components), is a system. Going to the doctor is a process, but health care is a system.
In the natural world, we say that there are systems. For example, the solar system of nine planets orbiting the sun. In the human body, we refer to such systems as the nervous system, the circulatory system, the digestive system, the reproductive system, and the respiratory system. The entire body is also referred to as a system in terms of physiology.
In addition, all so-called "things" (Objects) are actually systems. For example, a cup is an object, but it is also a system for holding hot or cold liquid, or other material. The cup has a certain shape and a handle, it is made of non-porous material and so on, and it is put together in such a way as to provide a useful function. Describing this thing makes up information, and defines a system.
(A number of material points considered simultaneously is called a system of material points, or briefly a system, if some common principle governs the collection.)
Types of systems
An open system can be influenced by events outside of the declared boundaries of a system. A closed system is self-contained: outside events can have no influence upon the system. In practice many things are a mixture of the two. For example a prison is a closed system because the prisoners can't get out, and the wardens spend most of their time at the prison. However it is also an open system, because it depends on outside factors and the prisoners and wardens do go outside. Dynamic systems have components or flows or both, that change over time.
Another distinction is the relation of physical systems to conceptual systems. Physical systems are systems of matter and energy. Conceptual systems are made up of ideas. Conceptual systems generally exist to aid in the accomplishment of specific goals or may be used to model physical systems.
Systems in information and computer science
In computer science and information science, system could also be a method or an algorithm. Again, an example will illustrate: There are systems of counting, as with Roman numerals, and various systems for filing papers, or catalogues, and various library systems, of which the Dewey Decimal System is an example. This still fits with the definition of components which are connected together (in this case in order to facilitate the flow of information).
System can also be used referring to a framework, be it software or hardware, designed to allow software to run, see platform.
Systems in operations research and management science
In operations research and organizational development (OD), organizations are viewed as human systems (conceptual systems) of interacting components such as sub-systems, processes and organizational structures. Organizational development theorist Peter Senge developed the notion of organizations as systems in his book The Fifth Discipline. Systems thinking has been identified as an important leadership competency where an individual thinks globally when acting locally. Such person takes into account the potential consequences of a decision on other parts of the organization.
Organizational theorists such as Margaret J. Wheatley have also described the workings of organizational systems in new contexts, such as quantum physics, chaos theory, and the self-organization of systems.
See also
- Chaos theory
- Complex systems
- Computer system
- Cybernetics
- Donella Meadows' twelve leverage points to intervene in a system
- General semantics
- Holarchy
- Meta-systems
- Socio-technical systems
- Solar System
- Systems theory
- Systems thinking
- Systems Ecology
References
- H.Hertz (1956) Principles of Mechanics, Dover, U.S.A.
External links
Wikipedia-Article "Software"
- "Software" redirects here. For other uses, see Software (disambiguation).
Computer software (or simply software) is that part of a computer system that consists of encoded information, as opposed to the physical computer equipment (hardware) which is used to store and process this information. The term is roughly synonymous with computer program but is more generic in scope.
The term "software" was first used in this sense by John W. Tukey in 1957. In computer science and software engineering, computer software is all information processed by computer systems, programs and data. The concept of software was first proposed by Alan Turing in an essay.
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Relationship to hardware
Computer software is so called in contrast to computer hardware, which is the physical substrate which is required to store and execute (or run) the software. In computers, software is loaded in RAM and executed on the central processing unit. At the lowest level, software consists of a machine language specific to an individual processor. Machine language consists of groups of binary values signifying processor instructions and data. Software is generally written in high-level languages that are easy and efficient for humans to use. High-level languages are compiled into machine language.
Relationship to data
Software has historically been considered an intermediary between electronic hardware and data, which the hardware processes according to instructions defined by the software. As computational science becomes increasingly complex, the distinction between software and data becomes less precise. Data has generally been considered as either the output or input of software. However, data is not the only possible output or input. For example, configuration information can also be considered input, although not necessarily considered data. The output of a particular piece of software may be the input for another piece of software. Therefore, software may be considered an interface between hardware, data, or software.
System, application and programming software
Practical computer systems divide software into three major classes: system software, application software and programming software, although the distinction is somewhat arbitrary, and often blurred.
- System software helps run the computer hardware and computer system. It includes operating systems, device drivers, diagnostic tools, servers, windowing systems, utilities and more.
- Application software allows a user to accomplish one or more specific tasks. Typical applications include office suites, business software, educational software, databases and computer games. Most application software has a graphical user interface (GUI).
- Programming software usually provides some useful tools to help programmer to write computer programs and software using different programming language in a more convenient way. The tools include text editor, compiler, interpreter, linker, debugger, and so on. Integrated development environment (IDE) merges those tools in a software bundle, and programmer may not need to type a lot of commands for compiling, interpreter, debugging, tracing, and etc., because IDE mostly has a GUI.
Software program and library
Software program is usually the directly executable part of a software. Software libraries are software components that are used by stand-alone programs, but which cannot be executed on their own.
Users see three layers of software
Users often see things differently than programmers. People who use modern general purpose computers (as opposed to embedded systems) usually see three layers of software performing a variety of tasks: platform, application, and user software.
- Platform software
- Platform includes the basic input-output system (often described as firmware rather than software), device drivers, an operating system, and typically a graphical user interface which, in total, allow a user to interact with the computer and its peripherals (associated equipment). Platform software often comes bundled with the computer, and users may not realize that it exists or that they have a choice to use different platform software.
- Application software
- Application software or Applications are what most people think of when they think of software. Typical examples include office suites and video games. Application software is often purchased separately from computer hardware. Sometimes applications are bundled with the computer, but that does not change the fact that they run as independent applications. Applications are almost always independent programs from the operating system, though they are often tailored for specific platforms. Most users think of compilers, databases, and other "system software" as applications.
- User-written software
- User software tailors systems to meet the users specific needs. User software include spreadsheet templates, word processor macros, scientific simulations, graphics and animation scripts. Even email filters are a kind of user software. Users create this software themselves and often overlook how important it is.
See also: Software architecture.
Software creation
Look back to Computer software
Software operation
Computer software has to be "loaded" into the computer's storage (also known as memory and RAM).
Once the software is loaded, the computer is able to operate the software. Computers operate by executing the computer program. This involves passing instructions from the application software, through the system software, to the hardware which ultimately receives the instruction as machine code. Each instruction causes the computer to carry out an operation -- moving data, carrying out a computation, or altering the flow of instructions.
Kinds of software by operation: computer program as executable, source code or script, configuration.
Software quality and reliability
Software reliability considers the errors, faults, and failures related to the creation and operation of software.
See Software quality, Software testing, and Software reliability.
Software patents
The issue of software patents is very controversial, since while patents protect the ideas of "inventors", they are widely believed to hinder software development. See Hacker ethic
See also
- Shared meanings: System software, Application software, Computer programs,