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 system into varying degrees of interdependence and independence across and "hide the complexity of each part behind an abstraction and interface". However, the concept of modularity can be extended to multiple disciplines, each with their own nuances. Despite these nuances, consistent themes concerning modular systems can be identified.
Composability is one of the tenets of functional programming. This makes functional programs modular.
Contextual nuances The meaning of the word "modularity" can vary somewhat based on context. The following are contextual examples of modularity across several fields of science, technology, industry, and culture:
Science In biology, modularity recognizes that organisms or metabolic pathways are composed of modules. In ecology, modularity is considered a key factor—along with diversity and feedback—in supporting resilience. In nature, modularity may refer to the construction of a cellular organism by joining together standardized units to form larger compositions, as for example, the hexagonal cells in a honeycomb. In cognitive science, the idea of modularity of mind holds that the mind is composed of independent, closed, domain-specific processing modules. Visual modularity, the various putative visual modules. Language module, the putative language module. In the study of complex networks, modularity is a benefit function that measures the quality of a division of a network into groups or communities.
Technology In modular programming, modularity refers to the compartmentalization and interrelation of the parts of a software package. In software design, modularity refers to a logical partitioning of the "software design" that allows complex software to be manageable for the purpose of implementation and maintenance. The logic of partitioning may be based on related functions, implementation considerations, data links, or other criteria. In self-reconfiguring modular robotics, modularity refers to the ability of the robotic system to automatically achieve different morphologies to execute the task at hand.
Industry In modular construction, modules are a bundle of redundant project components that are produced en masse prior to installation. Building components are often arranged into modules in the industrialization of construction. In industrial design, modularity refers to an engineering technique that builds larger systems by combining smaller subsystems. In manufacturing, modularity typically refers to modular design, either as the use of exchangeable parts or options in the fabrication of an object or the design and manufacture of modular components. In organizational design, Richard L. Daft and Arie Y. Lewin (1993) identified a paradigm called "modular organization" that had as its ground the need for flexible learning organizations in constant change and the need to solve their problems through coordinated self-organizing processes. This modular organization is characterized by decentralized decision-making, flatter hierarchies, self-organization of units.
Culture In The Language of New Media, author Lev Manovich discusses the principle that new media is composed of modules or self-sufficient parts of the overall media object. In contemporary art and architecture, modularity can refer to the construction of an object by joining together standardized units to form larger compositions, and/or to the use of a module as a standardized unit of measurement and proportion. In modular art, modularity refers to the ability to alter the work by reconfiguring, adding to, and/or removing its parts.
Modularity in different research areas Modularity in technology and management
The term is widely used in studies of technological and organizational systems. Product systems are deemed "modular", for example, when they can be decomposed into a number of components that may be mixed and matched in a variety of configurations.Schilling, M.A. 2000. "Towards a general modular systems theory and its application to inter-firm product modularity". Academy of Management Review, Vol 25:312–334.Baldwin, C. Y. & Clark, K. B. 2000. Design rules, Volume 1: The power of modularity, Cambridge, Massachusetts: MIT Press. The components are able to connect, interact, or exchange resources (such as energy or data) in some way, by adhering to a standardized interface. Unlike a tightly integrated product whereby each component is designed to work specifically (and often exclusively) with other particular components in a tightly coupled system, modular products are systems of components that are "loosely coupled."Orton, J. & Weick, K. 1990. "Loosely coupled systems: A reconceptualization". Academy of Management Review, 15:203–223.
In The Language of New Media, Lev Manovich proposes five "principles of new media"—to be understood "not as absolute laws but rather as general tendencies of a culture undergoing computerization."Manovich, J. 2001. The Language of New Media. Cambridge, MA: MIT Press. The five principles are numerical representation, modularity, automation, variability, and transcoding. Modularity within new media represents new media as being composed of several separate self-sufficient modules that can act independently or together in synchronisation to complete the new media object. In Photoshop, modularity is most evident in layers; a single image can be composed of many layers, each of which can be treated as an entirely independent and separate entity. Websites can be defined as being modular, their structure is formed in a format that allows their contents to be changed, removed or edited whilst still retaining the structure of the website. This is because the website's content operates separately to the website and does not define the structure of the site. The entire Web, Manovich notes, has a modular structure, composed of independent sites and pages, and each webpage itself is composed of elements and code that can be independently modified.Bradley Dilger, Review of The Language of New Media (Kairos: http://english.ttu.edu/kairos/7.1/reviews/dilger/).
Organizational systems are said to become increasingly modular when they begin to substitute loosely coupled forms for tightly integrated, hierarchical structures.Schilling, M.A. & Steensma, K. 2001. "The use of modular organizational forms: An industry level analysis". Academy of Management Journal, 44: 1149–1169. For instance, when the firm utilizes contract manufacturing rather than in-house manufacturing, it is using an organizational component that is more independent than building such capabilities in-house: the firm can switch between contract manufacturers that perform different functions, and the contract manufacturer can similarly work for different firms. As firms in a given industry begin to substitute loose coupling with organizational components that lie outside of firm boundaries for activities that were once conducted in-house, the entire production system (which may encompass many firms) becomes increasingly modular. The firms themselves become more specialized components. Using loosely coupled structures enables firms to achieve greater flexibility in both scope and scale. This is in line with modularity in the processes of production, which relates to the way that technological artifacts are produced. This consists of the artifact's entire value chain, from the designing of the artifact to the manufacturing and distribution stages. In production, modularity is often due to increased design modularity. The firm can switch easily between different providers of these activities (e.g., between different contract manufacturers or alliance partners) compared to building the capabilities for all activities in house, thus responding to different market needs more quickly. However, these flexibility gains come with a price. Therefore, the organization must assess the flexibility gains achievable, and any accompanying loss of performance, with each of these forms.
Modularization within firms leads to the disaggregation of the traditional form of hierarchical governance.Miles R.E., Snow, C.C., Mathews, J.A., Miles, G., & Coleman, H.J. "Organizing in the knowledge age — Anticipating the cellular form". Academy of Management Executive 11(4):7–20.Zenger, T.R. & Hesterly, W.S. "The Disaggregation of Corporations — Selective Intervention, High-powered Incentives, and Molecular Units". Organization Science 8:209–222.Kuntz, L. & Vera, A. 2007. "Modular organization and hospital performance". Health Services Management Research, 20(1): 48–58. The firm is decomposed into relatively small autonomous organizational units (modules) to reduce complexity. Modularization leads to a structure, in which the modules integrate strongly interdependent tasks, while the interdependencies between the modules are weak. In this connection the dissemination of modular organizational forms has been facilitated by the widespread efforts of the majority of large firms to re-engineer, refocus and restructure. These efforts usually involve a strong process-orientation: the complete service-provision process of the business is split up into partial processes, which can then be handled autonomously by cross-functional teams within organizational units (modules). The co-ordination of the modules is often carried out by using internal market mechanisms, in particular by the implementation of profit centers. Overall, modularization enables more flexible and quicker reaction to changing general or market conditions. Building on the above principles, many alternative forms of modularization of organizations (for-profit or non-profit) are possible. However, modularization is not an independent and self-contained organizational concept, but rather consists of several basic ideas, which are integral parts of other organizational concepts. These central ideas can be found in every firm. Accordingly, it is not sensible to characterize a firm as "modular" or as "not modular", because firms are always modular to some degree.
The accounts above largely assume a proprietary setting, in which modularity serves to manage scarce resources and to outsource production. Kosmas Gavras and Vasilis Kostakis argue that open-source hardware inverts several of these premises: contributors self-select tasks, the copying of technical knowledge is encouraged rather than restricted, and economies of scale sit uneasily with localised manufacturing. Extending the distinction between modularity in artifact design, in production processes and in use, they propose a five-part typology comprising design modularity (which may rest on physical modules or on intangible ones, such as reusable blocks of parametric design code), fabrication modularity, hardware modularity, macro-modularity across a project ecosystem, and community modularity among contributors. They identify intangible design, fabrication and macro-modularity as particular to the open-source context, where the aim is not to outsource component production but to allow designs to be adapted to whatever tools and materials are locally available.