Software documentation

People write notes for computer programs. These notes are called documentation. They use words and pictures. They explain how a program works. They also show how to use it.

Some notes help the people who build the program. These notes list what the program should do. They help everyone agree on the plan. This makes it easier to change the program later.

Other notes are for the people using the program. These are like manuals. They can show you each step to finish a task. They can also group ideas by topic.

Notes can be in books or on a screen. They help people find answers fast. Good notes make the work better and save time. Documentation is a big part of making software.

Software documentation is a set of notes for computer programs. These notes use words and pictures. They explain how a program works. They also show how to use it.

One type is requirements documentation. This describes what a program should do. It helps everyone agree on a plan. This is very important for complex tools. It is also vital for safety-critical software. This includes tools for medical machines or power systems. Good notes help prevent mistakes. They also save time and money.

Another type is architecture documentation. This gives a big-picture view of the software. It does not focus on small code details. Instead, it shows how parts fit together. Some people use trade studies to help. A trade study looks at different ways to solve a problem. It lists the good and bad parts of each way. This helps people find the best solution.

Technical documentation is for the people who build the code. Some tools can auto-generate these notes. This means the computer makes the notes from the code itself. This helps keep the notes up to date. Finally, user documentation helps the people using the program. These can be tutorials that guide you step by step.

Software documentation is a collection of written text and pictures. These notes help people understand computer software. Some notes are tucked inside the code itself. Other notes are separate guides for people to read. Documentation is a very important part of software engineering. It helps everyone involved know exactly what a program is supposed to do.

There are many different ways this work happens. First, engineers create requirements documentation. This describes the qualities and capabilities a system must have. It acts as a foundation for the whole project. Next, they write architecture or design documentation. This provides a big-picture overview of the software. It shows how different parts relate to each other. Finally, they create technical documentation for the actual code.

People have found better ways to manage these notes over time. In the past, people mostly used word processors or spreadsheets. Now, many use special tools to manage complex requirements. In Agile development, people use something called user stories. These are short descriptions of what a user needs. These stories often belong to a larger group called an epic. An epic is a broad set of related tasks.

Different roles require different kinds of facts and numbers. Requirements documentation is used by many people. This includes customers, project managers, and testers. It is also used by developers and marketing teams. For safety-critical software, the notes must be very formal. This applies to medical equipment or nuclear power systems. For small apps that only last a month, very little documentation is needed.

Documentation also helps people learn how to use new tools. User documentation describes the features of a program. It can be a tutorial that guides you step by step. It can also be thematic, which means it focuses on specific areas. Some technical notes are even made by computers. Tools like Javadoc or Doxygen can auto-generate notes from the code. This helps keep the information up to date for everyone.

Software documentation consists of written text or illustrations that accompany computer software. It can be embedded directly within the source code or exist as separate files. This documentation serves to explain how software operates or how to use it. Because different people have different roles, documentation can mean different things to different users. It is a vital component of the software engineering process. Without it, managing complex systems becomes much more difficult.

The process often begins with requirements documentation. This is a description of what a software system must do or its specific qualities. It acts as a foundation or an agreement for what will be implemented. Requirements are used by many people, including customers, project managers, and developers. They can be written in natural language, drawn as figures, or expressed as mathematical formulas. Sometimes requirements are implicit and hard to uncover. If requirements are missing, software changes become more expensive and error-prone. The level of detail needed often depends on the software's complexity or its life expectancy.

Architecture or design documentation provides a high-level overview of the software. These documents are often described as a third derivative from the code. They do not explain how to program a specific routine. Instead, they list the general requirements that motivate a routine's existence. A good architecture document focuses more on explanation than on tiny details. Another design tool is the trade study, often presented as a whitepaper. A trade study examines one specific aspect of a system. It describes different alternatives and lists the pros and cons of each. This should be an impartial, scientific endeavor rather than a marketing tool.

In enterprise development, the Database Design Document (DDD) is very important. This document contains conceptual, logical, and physical design elements. It creates a common source of information for database designers, developers, and administrators. For relational database systems, the DDD must include an Entity-Relationship Schema. This schema defines entity sets, their attributes, and their relationships. It also includes details like candidate keys and constraints. It is vital to update these documents whenever any change occurs in the database. This ensures all actors in the development scene have accurate information.

Technical documentation often focuses on the code itself. This includes README files and Application Programming Interface (API) documentation. Technical notes are used by developers, testers, and sometimes end-users. In high-end fields like aerospace or medical equipment, this documentation is critical. Good code documentation can actually reduce the costs of maintaining software. Many programmers use a reference guide style to look up functions quickly. Some tools, such as Javadoc or Doxygen, can auto-generate this documentation. These tools extract comments from the source code to create HTML or text files. This makes it easier to keep the documentation up to date.

Some computer scientists advocate for new ways to handle documentation. Donald Knuth suggested literate programming (LP). In LP, documentation is written at the same time and place as the source code. While languages like Haskell have some support for this, it is not widely used. Another approach is the "Docs as Code" method. There is also elucidative programming, which is a practical application of literate programming. This paradigm suggests that source code and documentation should be stored separately. This helps developers access information during activities like code walks or porting software.

Finally, user documentation is designed specifically for the person using the program. Unlike code documents, these describe how to use the features of an application. User documentation is often seen as a contract specifying what the software will do. It must be consistent, simple, and include a thorough index. There are three main ways to organize this information. A tutorial approach guides new users through tasks step by step. A thematic approach organizes chapters by specific areas of interest. These guides help users realize the full potential of the software they are using.