How to write a functional specification

Paul Waine Share this item with your network: The functional specification is a kind of guideline and continuing reference point as the developers write the programming code. At least one major product development group used a "Write the manual first" approach.

How to write a functional specification

It does not specify the interface between an application and either a PNG encoder, decoder, or editor. The precise form in which an image is presented to an encoder or delivered by a decoder is not specified. Four kinds of image are distinguished. The source image is the image presented to a PNG encoder.

The reference image, which only exists conceptually, is a rectangular array of rectangular pixels, all having the same width and height, and all containing the same number of unsigned integer samples, either three red, green, blue or four red, green, blue, alpha.

The array of all samples of a particular kind red, green, blue, or alpha is called a channel. Each channel has a sample depth in the range 1 to 16, which is the number of bits used by every sample in the channel.

Different channels may have different sample depths. The red, green, and blue samples determine the intensities of the red, green, and blue components of the pixel's colour; if they are all zero, the pixel is black, and if they all have their maximum values 2sampledepth-1the pixel is white.

The alpha sample determines a pixel's degree of opacity, where zero means fully transparent and the maximum value means fully opaque. In a three-channel reference image all pixels are fully opaque. It is also possible for a four-channel reference image to have all pixels fully opaque; the difference is that the latter has a specific alpha sample depth, whereas the former does not.

Each horizontal row of pixels is called a scanline. Pixels are ordered from left to right within each scanline, and scanlines are ordered from top to bottom. A PNG encoder may transform the source image directly into a PNG image, but conceptually it first transforms the source image into a reference image, then transforms the reference image into a PNG image.

What is a Functional Specification (FS)? - Definition from Techopedia

Depending on the type of source image, the transformation from the source image to a reference image may require the loss of information. That transformation is beyond the scope of this International Standard. The reference image, however, can always be recovered exactly from a PNG datastream.

The PNG image is obtained from the reference image by a series of transformations: Five types of PNG image are defined see 6.

how to write a functional specification

Colour types and values. If the PNG encoder actually transforms the source image directly into the PNG image, and the source image format is already similar to the PNG image format, the encoder may be able to avoid doing some of these transformations.The OWL 2 Web Ontology Language, informally OWL 2, is an ontology language for the Semantic Web with formally defined meaning.

OWL 2 ontologies provide classes, properties, individuals, and data values and are stored as Semantic Web documents.

Functional specifications are an essential step in building quality software that you’ll want to support over the long term. They define the requirements to be implemented in the software. A good specification needs to carefully describe how the software will look and behave in all situations.

Because nobody likes building or using a poor requirements document. Over the past year, our team has probed dozens of engineers and their requirements documents to create the ultimate list of tips on how to write requirements documents that are a dream to work with..


It has become clear that enormous numbers of engineering design errors originate in the requirements document. With over 20 years of experience, we are one of the leading solutions providers in Supply Chain & Logistics and Manufacturing domain, with a strong presence in Business Intelligence, Managed Application Services and Software Testing Segments.

May 08,  · How to Write a Technical Specification Three Parts: Assessing General Considerations Creating the Specification Completing the Specification Community Q&A A technical specification is a document that defines a set of requirements that a product or assembly must meet or exceed%(21).

By Darren Levy updated on March 28, What are software requirements specification (SRS)? Software requirements specification capture system behavior as opposed to non-functional requirements specifications which define attributes as not behavior.

This 'functionality' refers to services, tasks or functions the user performs using the system in question.

Portable Network Graphics (PNG) Specification (Second Edition)