System


 * For the Macintosh operating system, which was called System up to version 7.5.5, see Mac OS.

A system is an assemblage of inter-related elements comprising a unified whole. From the Latin and Greek, the term "system" meant to combine, to set up, to place together. A sub-system is a system which is part of another system. A system typically consists of components (or elements) which are connected together in order to facilitate the flow of information, matter or energy. The term is often used to describe a set of entities which interact, and for which a mathematical model can often be constructed.

Background
At arbitrary 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&mdash;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.

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.

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.

Elements which can also be called systems
Many of the systems mentioned previously are related to science and technology. There are other systems
 * In sport, there is what's called a scoring system. Examples are:
 * In rugby union, a try is worth 5 points, a goal which is not a conversion is worth 3 points, and a conversion is worth 2 points.
 * In rugby league, a try is worth 4 points, a goal which is not a drop-goal is worth 2 points, and a drop-goal is worth 1 point.
 * In soccer, netball, waterpolo, lacrosse, korfball, and field hockey, scoring is based solely on the number of goals scored.
 * In ice hockey, you can also score points by helping a team-mate to score a goal.
 * Buzkashi scores are solely dependent on how many goats have been thrown in the goal.
 * In baseball and cricket, scoring is based on the number of runs completed.
 * In basketball, 1 point is scored for a free throw, 2 points for a lay-up or a shot scored by someone in the circle, and 3 points for a shot scored by someone outside the circle.
 * In archery, your score depends on how accurate your shot was.
 * In tennis and volleyball, you score a point if the ball goes right past your opponents.
 * In American football, a touchdown is worth 6 points, a field goal is worth 3 points, a conversion can be worth 1 or 2 points, and a safety is worth 1 point. The same system applies in Canadian football.
 * In hurling and Gaelic football, a goal is worth 3 points and if the ball goes over the goal but through the posts, you score 1 point.
 * In Australian rules football, a goal is worth 6 points and a behind is worth 1 point.
 * The scoring system of International rules is a combination of Australian rules and Gaelic football. A goal is worth 6 points, an over (which is when the ball misses the goal but goes through the post) is worth 3 points, and a behind is worth 1 point.
 * In golf, where you have to aim for a lower score instead of a higher score, the score can be based solely on the number of strokes taken, or that number minus a "par" which changes from hole to hole.
 * Scoring systems also apply in card games. Click on the link for more.
 * Families can also introduce discipline systems for their children. This might include time-out, grounding, removal of priveleges, etc.