Software requirements specification. What do you need to know.

Comply with each of the details and requirements defined in the software project that is carried out, is the big goals that a developer must achieve to meet the expectations of their customers and make the project successful. How can a developer create systems that meet all the requirements of their customers? It can be one of your first questions.

The thing is that there are a lot of factors influence the success of the software project. But today we will talk about an essential document that should be prepared at the early stages of product development. We are talking about the Software Requirements Specification Document.

The Software Requirements Specification (SRS) is undoubtedly considered as one of the most critical phases of the software/product development. SRS — Software Requirement Specification — a special software documentation that contains information on how the system itself should behave, what functions it should perform, what load it should withstand, and so on. Product requirements document is the place where the characteristics and requirements of software, product, program or set of programs are described. These elements are expressed in natural language, without considerations or technical terms.

Why do we need to write SRS?

• You can get an accurate estimate of the cost, risk and time costs.
• The client will be able to form their vision of the project more clearly.
• The customer and the contractor will have the same idea about the product.
• It will help identify the optimal set of functions.
• It serves as the basis for the formation of other technical documentation.
• The development process will be optimized and time minimized.
• There will be no duplication of tasks.
• Allows you to structure problems to solve them easier and faster.

It has become very evident that a poor specification of software requirements can lead to failed projects. Hence, this discipline becomes increasingly essential.

How to prepare a product requirements document?

The following template follows the guidelines established in the IEEE 830 standard, according to which the software requirements specification should contain the description of the functionality of the application, relationship with external systems and non-functional requirements such as performance, availability, response times, and maintainability between others.

The template to prepare the software requirements document is divided into the following sections:

Purpose:

You should add a name or title of a product that is specified in the paper, including its version number or release. Describe which elements or parts of the scope of the software are included in the document, establish whether it covers the entire software, only one part of it, subsystem or subgroup of processes.

The scope of the software:

There should be a brief description of the range of the software that is being specified, including purpose or general objective, benefits provided to the business and organization area, the relation of the software objectives with the corporate goals and business strategies. You can refer to other documents.

References:

Here you can include other printed documents, electronic documents or electronic addresses that complement the product requirements document.

Product functionalities:

Each feature can be composed of one or several functional software requirements. Only a numbered list of the main functionalities should be included.

Users characteristics:

In this section, you should describe that users who will use this product. Classify them on the base of the regularity of use, a group of functionalities used, security privileges, experience level, and other parameters.

Operating environment:

The environment in which the system, software, module or group of functionalities will be developed also should be included. Mention such aspects as versions of the operating system, the hardware platform, and other systems or elements with which it must coexist.

Functional requirements:

List the features, and for each of them, note the functional requirements. They can also be documented in a requirements’ traceability matrix.

Business rules:

This part contains those principles that must apply to the whole set of software specifications listed in the document. For example, explain which individuals can play a specific role under certain circumstances.

External interfaces requirements:

This chapter includes interfaces with the hardware, interfaces with other systems and communication interfaces, characteristics and attributes of user interfaces (GUI).

Non-functional requirements:

They specify criteria to evaluate the operation of an information technology service, in contrast to the functional requirements that define specific behaviors.

Other requirements:

Include those requirements that are not explained in any other section of the product requirements document. It can be database requirements, internationalization, legal and reuse objectives of software components.

Glossary:

Add a description of terms and acronyms necessary for understanding of the created document.

Tips to write SPS

• Describe everything very briefly and clearly as much as possible.
• Don’t include things that may not need to be documented.
• Write without vague descriptions. A person reading the SRS must understand precisely what is written, and not something else.
• Visualize. For example, use DFD (data flow diagrams) diagrams. The specification cannot be complete if we do not know what is at the entrance to the described software, and what is at the output. Everything must be included.

Now you have all the main elements that will help you to make Software Requirements Specification. Go for it!