What Is a System?

This chapter defines a System, the broadest of the core terms used in this document. Because an Application is a specific kind of System, the definition of System must be understood first.

Definition

A System is any combination of people, processes, tools, technologies, materials, and data and information — including other Systems — that work together to achieve one or more defined purposes, such as solving a specific problem or challenge.

What the Definition Includes and Implies

The definition is intentionally broad. A System is not limited to technology. A payroll operation, for example, is a System that combines people (payroll staff), processes (pay cycles and approvals), tools and technologies (one or more Applications), and data and information (employee, time, and tax records) to achieve a defined purpose: paying employees correctly and on time.

Several points follow from the definition:

• Systems contain other Systems. A System is frequently composed of smaller Systems, and is frequently part of larger ones. An Application is a System; the business operation it supports is a larger System that contains it.

  

• Figure: Nested Systems illustrating an Application as a technical component within a broader business System, which operates within the enterprise and interacts with other internal and external Systems. Shows how people, business processes, information, technology, and Applications work together to deliver business capabilities and outcomes.

• Purpose defines the System. What makes a collection of parts a System is that they work together toward one or more defined purposes. Identifying the purpose is the first step in identifying the System.

• Repeatability is not required. A System does not have to behave in an automated or highly repeatable way. That characteristic is what distinguishes Applications from Systems in general, as the next chapter explains.

• “Software system” is descriptive, not a separate term. This document does not define separate terms for software systems, technical systems, or socio-technical systems. Where those phrases appear, they describe a kind of System rather than introduce a new governed term.

Why the Definition Matters for Application Management

Application Management is concerned with Applications, but Applications never operate alone. Every Application exists inside larger Systems made up of the people who use and support it, the processes it automates, the other Applications it exchanges data with, and the infrastructure it runs on. Seeing the Application as one System within others is what makes it possible to document it properly: its users, its supporting processes, its Integrations, and its dependencies are all part of the picture.

Best Practice: Describe Every Application in the Context of the Larger Systems It Serves

When documenting an Application, describe not only the Application itself but also the larger Systems it is part of: the business operations it supports, the people and teams who use and run it, and the other Applications and Systems it depends on or serves.

Benefits: An Application documented in isolation tells readers what it is but not why it matters or what breaks when it fails. Documenting its place within larger Systems lets support teams judge the business impact of an incident, lets architects assess the ripple effects of a change, and lets leaders see which business operations depend on which Applications.

Connections to Related IF4IT Practices and Inventories

The Systems Development Lifecycle (SDLC) Best Practices uses the term System in the context of how Assets, Products, Services, Systems, Applications, and Solutions relate to the lifecycle. The IF4IT Enterprise Model and Modeling Best Practices describes how Systems and their relationships are represented in an enterprise-wide model.