Let’s imagine that you order a cake for your daughter’s Birthday. Your daughter likes Barbie dolls, pink colors, and unicorns. Thus, to receive the cake you want, translate this information to your baker so that you’ll receive a cake your daughter will like 100%.
The same goes for IT project development… but without unicorns. Since the cost of software development is much higher than the cost of a cake, you must clearly understand what your software should and shouldn’t do beforehand to avoid costly mistakes.
Since 2007 the IntelliSoft team has been providing software development services. And the better the client defines requirements for an IT project, the better the outcome. For that reason, we’ve created this article to tell what is software requirement specifications, its type, and what information such a document must contain.
Table of Contents
What Is a Software Requirement Specification?
Imagine you’re a designer, QA engineer or programmer. Your team got an exciting project. What would you start with first? Designing the user interface? Fixing bugs? Or with the code? Anyone with basic knowledge of the engineering process in IT would start with documentation. Defining the essential features of the future product as well as all operational processes is the most important thing when beginning to work on a new IT project.
What’s a SRS? And how to approach it correctly?
The SRS is a crucial document for the project manager. He relies on it for discussions with the development team. The managers in IT are usually busy with operational processes. On this account, they commonly do not have the time and opportunity to check the code generated by the programmers.
The SRS is the starting point for the development and implementation teams. Depending on the structure of the development team and the corporate culture, team members might also be involved in the earliest stages of the primary requirements development phase. But what the code should do has to be decided based on the SRS. It’s also the most important document for the QA engineers.
Why Is a Well-Defined SRS Document So Important?
Undocumented requirements lead to inevitable misunderstandings. It is not uncommon for the client’s side and the development team to understand the same terms differently. Especially if we are talking about outsourced staff. Outsourced developers are often not familiar with the customer’s business.
QA professionals are the ones who truly understand the importance of a well-defined SRS. When the project SRS isn’t clear, QA specialists are the ones who always take the brunt. Imagine trying to determine if the new software is being developed correctly without guidelines on what exactly it should do. This is just insane.
QA engineers aren’t the only ones who get in trouble without a clear SRS. The whole IT team cannot function without documentation.
Any misunderstandings due to the lack of specifications lead to constant improvements, changes and bug fixes. There is a chance that everything goes according to the plan without documented requirements, but it is way too low to rely on it. Typically, this causes problems. The deadlines are missed and the project’s costs are sky-high.
To ensure smooth development and implementation, all parts of the development process must be clearly understood by each team member in the same way. A SRS is drawn up to enable developers to see each feature of the future product exactly as the client sees it.
Do you need a detailed guide on how you can write a requirements document? Don’t worry: There are many sites where you can find a great software requirement document template.
The Main Types of Software Requirements
There are two main types you should remember:
- Functional prerequisites. What is the purpose of the developed system? What user needs should it satisfy? As the name suggests, functional prerequisites describe the functionality of the software.
- Non-functional prerequisites. How will the software do what it’s designed to do? What are the tasks of the development team? Non-functional prerequisites describe how exactly the developed system should behave.
These two go hand in hand. The first complement and define the second ones.
Without specification of all system parameters, it’s impossible to tell if the system’s functions are designed as they should be. Hence the project requirements should be carefully reviewed and documented.
The Structure of a SRS Document
There are lots of software requirement specification samples out there. But all the examples you might find are pretty much the same.
Here is a standard structure of a SRS:
- Short introduction
- Intended audience
- Project scope
- General Description
- Product vision
- Product functionality
- Core audience
- Operating environment
- User documentation
- Scope, constrains, rules, standards
- System functionality
- Functional block (there can be several functional blocks)
- Description and priority
- Functional requirements
- Functional block (there can be several functional blocks)
- External interfaces
- User interfaces
- Programming interfaces
- Hardware interfaces
- Communication interfaces
- Non-functional requisitions
- Performance pre-requisites
- Data prerequisites
- Software quality criteria
- System security prerequisites
- Other requisitions
Basic Requirements for All Document Sections
You’ll easily find a software requirement specification template somewhere on the Internet. But remember, the fact you found it on the web doesn’t mean it is correctly written.
Another important thing is the level of detail. The SRS is complete if it does not cause confusion and describes the functionality of the future product to a sufficient extent.
Why Should You Use Specialized Tools?
SRS document tracking tools are mechanisms that help eliminate assumptions from projects. These tools replace assumptions and ambiguity with facts and certainty. They can help you easily verify that the product works exactly as it should. All you have to do is to implement these tools into your day-to-day workflow.
Popular tools like Microsoft Word and Google Spreadsheets can be considered a very simple alternative to professional mechanisms. They can be easily used to register and track data. However, they aren’t scalable and can be complicated because everything has to be done manually by the designated project manager. This is where advanced tools come into play.
Sure, it is possible to write a good SRS document in Microsoft Word or Google Spreadsheets. The problem with this common approach is that it can be tedious and time-consuming to go this way. The point is that even relatively light-load software engineering projects can take a lot of effort. And when requirements change, the limits of popular, simple tools are reached.
Instead of facing obstacles later in the software engineering process, it is much better to use specialized tools right from the start. Such tools provide support and ultimately increase your team’s productivity.
Before selecting a tool, determine the main goals of the product to be developed. There are dozens of different tools out there that have their strengths and weaknesses. Remember to always keep the project’s main goals in mind. Make sure you know what you should achieve when the development process is done
A great tracking mechanism can do much more than just being a reference point for reviewing the functionality. Tracking mechanisms that can be described as good are able to function as a sort linchpin between the parties involved.
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The Characteristics of a Great SRS
The IEEE specification 830-1998 describes the methods and recommended approaches for the software requirements specification definition. If you’ve never written a SRS, it should help you with defining the pre-requisites for any development project.
With reference to Kurosh Farsimadan’s blog, the use of SRS eliminates and prevents problems during the design stage. At this stage, any conflicting pre-requisites and functions can be effortlessly corrected.
It is much cheaper to make changes early. Early on, you can route your development process, simply structuring problems in a way that makes them easy to solve.
Let’s have a look at what make truly good requirements:
The explicitness of the final SRS is verified by both the client and the development team on the basis of an agreement signed between the client and the contracted company.
The main goal of a SRS is to eliminate misunderstandings. This is why every single specification must have only one possible interpretation. It is not uncommon to include a glossary to make the SRS more accurate. It’s considered good style.
The more complex the developed product, the more detail should be included. A specification should cover everything from performance requirements to functionality.
Internal consistency means that no statements in the final SRS can contradict other statements in the same SRS. This is another reason for including a glossary – so that any object and process is labeled with a precise term.
Often, there can be mandatory and desirable requirements. It is important to clearly identify both types, so that the designated project manager can create a step-by-step project plan.
There must always be a way to validate each prerequisite included in the document. For a project pre-requisites to be considered verifiable, it must be measurable.
This point is related to the structure of the document. Every requirement included in the doc should be easily changeable in order not to disrupt the project workflow when changes need to be made.
The designated project manager should be able to assess the quality of the work. To be able to do this, he has to understand how to measure progress.
Checking Your Project’s SRS
Every requirement included in the SRS must be easily verifiable. The most common methodology for testing your SRS is to conduct tests. If verification by tests isn’t possible, another method should be picked instead. Other methods include analysis, demonstration, inspection and the design review at an early stage.
Some requirements, by their very nature, aren’t verifiable. These include specific requirements that say that the system should never, or always should, behave in a certain, fixed manner. Properly testing these requirements would require an endless testing cycle. Such requirements must be redefined to be verifiable.
Non-functional requirements that cannot be verified should still be retained as documentation of the client’s intent. Such information can be translated into process requirements. Consider a specific requirement that states that the developed software must not contain “backdoors”. Such a specific clause can be replaced with the requirement to use pair programming.
SRS documents are prone to problems of ambiguity, incompleteness, and inconsistency. Removing them at the stage of requirements documentation costs less than removing these later during design or software development. That’s why checking the SRS document at the very beginning of the development process is crucial. Without it, the organization could suffer big losses.
How We Can Help
If this informative article turned out to be quite interesting and useful for you, you’re probably in IT. And if you have read up to this point now, you’re one of those people who are dedicated and eager to find and implement new solutions.
Are you truly satisfied with all the processes happening within your company? Do you want to change some things for the better? How about hiring a project manager, who is a pro in writing good documentation? Or a software developer, who knows how to meet the client’s needs?
Don’t wait to bring your ideas to life. At IntelliSoft, you can hire an experienced developer or a dedicated team consisting of field experts, who will take care of the hard stuff while you’re focusing on your main business goals.
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