Composability is a
system design principle that deals with the inter-relationships of components. A highly composable system provides components that can be selected and assembled in various combinations to satisfy specific user requirements. In information systems, the essential features that make a component composable are that it be:
* self-contained (
modular
Broadly speaking, modularity is the degree to which a system's components may be separated and recombined, often with the benefit of flexibility and variety in use. The concept of modularity is used primarily to reduce complexity by breaking a s ...
): it can be deployed independently – note that it may cooperate with other components, but dependent components are replaceable
*
stateless: it treats each request as an independent transaction, unrelated to any previous request. ''Stateless'' is just one technique; ''
managed state'' and ''
transactional'' systems can also be composable, but with greater difficulty.
It is widely believed that composable systems are more
trustworthy than non-composable systems because it is easier to evaluate their individual parts.
Simulation theory
In
simulation
A simulation is the imitation of the operation of a real-world process or system over time. Simulations require the use of models; the model represents the key characteristics or behaviors of the selected system or process, whereas the s ...
theory, current literature distinguishes between Composability of Models and Interoperability of Simulation. Modeling is understood as the purposeful abstraction of reality, resulting in the formal specification of a conceptualization and underlying assumptions and constraints.
Modeling and simulation
Modeling and simulation (M&S) is the use of models (e.g., physical, mathematical, or logical representation of a system, entity, phenomenon, or process) as a basis for simulations to develop data utilized for managerial or technical decision makin ...
(M&S) is, in particular, interested in models that are used to support the implementation of an executable version on a computer. The execution of a model over time is understood as the simulation. While modeling targets the conceptualization, simulation challenges mainly focus on implementation, in other words, modeling resides on the abstraction level, whereas simulation resides on the implementation level. Following the ideas derived from the Levels of Conceptual Interoperability model (LCIM), Composability addresses the model challenges on higher levels,
interoperability
Interoperability is a characteristic of a product or system to work with other products or systems. While the term was initially defined for information technology or systems engineering services to allow for information exchange, a broader defi ...
deals with simulation implementation issues, and
integratability with network questions. Tolk
[Tolk, A. ''Interoperability, Composability, and their Implications for Distributed Simulation - Towards Mathematical Foundations of Simulation Interoperability''. Proceedings DS-RT 2013 Conference, Delft, The Netherlands, October 2013] proposes the following definitions: Interoperability allows exchanging information between the systems and using the information in the receiving system. Composability ensures the consistent representation of truth in all participating simulation systems of the federation.
See also
Examples
*
Composable operations
*
Minimal structured control flow
*
Universal composability The framework of universal composability (UC) is a general-purpose model for the analysis of cryptographic protocols. It guarantees very strong security properties. Protocols remain secure even if arbitrarily composed with other instances of the sam ...
Related concepts
*
Function composition
*
Object composition
In computer science, object composition and object aggregation are closely related ways to combine objects or data types into more complex ones. In conversation the distinction between composition and aggregation is often ignored. Common kind ...
*
Principle of compositionality
In semantics, mathematical logic and related disciplines, the principle of compositionality is the principle that the meaning of a complex expression is determined by the meanings of its constituent expressions and the rules used to combine them. ...
References
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Software engineering terminology