Modularity

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.

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:

The term modularity 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. 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."

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." 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.

Organizational systems are said to become increasingly modular when they begin to substitute loosely coupled forms for tightly integrated, hierarchical structures. 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. 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 a some degree.

Input systems, or "domain specific computational mechanisms" (such as the ability to perceive spoken language) are termed vertical faculties, and according to Jerry Fodor they are modular in that they possess a number of characteristics Fodor argues constitute modularity. Fodor's list of features characterizing modules includes the following: