computer science

Software component

Software component is a computer science topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Software component rather than just read about it. In short: A software component is a modular unit of software that encapsulates specific functionality. The desired characteristics of a component are reusability and maintainability.

Key takeaways

Software component belongs to computer science; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Software component to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Software component from memory before moving on to harder problems.

Reference excerpt

A software component is a modular unit of software that encapsulates specific functionality. The desired characteristics of a component are reusability and maintainability.

Value Components allow software developers to assemble software with reliable parts rather than writing code for every aspect. It makes implementation more like factory assembly than custom building.

Attributes Desirable attributes of a component include but are not limited to:

Cohesive – encapsulates related functionality Reusable Robust Substitutable – can be replaced by another component with the same interface Documented Tested

Third-party Some components are built in-house by the same organization or team building the software system. Some are third-party, developed elsewhere and assembled into the software system.

Component-based software engineering For large-scale systems, component-based development encourages a disciplined process to manage complexity.

Framework Some components conform to a framework technology that allows them to be consumed in a well-known way. Examples include: CORBA, COM, Enterprise JavaBeans, and the .NET Framework.

Modeling

Component design is often modeled visually. In Unified Modeling Language (UML) 2.0 a component is shown as a rectangle, and an interface is shown as a lollipop to indicate a provided interface and as a socket to indicate consumption of an interface.

History The idea of reusable software components was promoted by Douglas McIlroy in his presentation at the NATO Software Engineering Conference of 1968. (One goal of that conference was to resolve the so-called software crisis of the time.) In the 1970s, McIlroy put this idea into practice with the addition of the pipeline feature to the Unix operating system. Brad Cox refined the concept of a software component in the 1980s. He attempted to create an infrastructure and market for reusable third-party components by inventing the Objective-C programming language. IBM introduced System Object Model (SOM) in the early 1990s. Microsoft introduced Component Object Model (COM) in the early 1990s. Microsoft built many domain-specific component technologies on COM, including Distributed Component Object Model (DCOM), Object Linking and Embedding (OLE), and ActiveX.

References

Worked examples

Example 1 — a first encounter with Software component

Start with the simplest possible case. Write down what Software component claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In computer science, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Software component before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Software component ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Software component

In research: Software component appears in computer science research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Software component in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Software component is common in secondary-school and first-year university syllabi. It links to neighbouring topics Software architecture, Software development, Software engineering, so understanding it makes those chapters shorter.
In everyday life: Look for Software component outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Software component in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Software component means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Software component out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Software component in simple terms?

A software component is a modular unit of software that encapsulates specific functionality. The desired characteristics of a component are reusability and maintainability.

Why does Software component matter?

Because it connects several computer science ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Software component?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Software component.