Presented by Charley Tichenor
Session Description: Functional software describes “what” the software will do. IFPUG interprets these aspects as external inputs, external outputs, external inquiries, internal logical files, and external files. Non-functional software describes “how” the software will do it. In many situations, the work effort to develop the “how” portion of the software can be more complex and time-consuming that that of delivering the “what.” The non-functional size of software can be measured by considering four categories and 14 subcategories of software requirements. The purpose of this presentation is to describe the thinking behind non-functional software, its sizing, and how sizing non-functional software can contribute to better cost and schedule forecasts for software development work. We will also reference the corresponding international measurement standards.
Charley Tichenor has been a member of IFPUG since the early 1990s. He is currently Vice-Chair of the Non-functional Sizing Standards committee and member of the Business Applications committee. He has participated with the SNAP development team since 2011. He is a semi-retired Adjunct Professor at Marymount University in Arlington, Virginia, USA.