Using COSMIC for the Functional Size Measurement of Distributed Applications in Cloud Environments

Ferrucci, F., Gravino, C. and Salza, P.

The competitiveness of software companies greatly depends on the ability of their project managers to carry out a reliable and accurate software size estimation. Among the approaches for software sizing, functional size measurement (FSM) methods are widely used in the industry since they can be applied early, based on the user functional requirements. COSMIC represents a second-generation FSM method, and its adoption is rapidly growing in the software industry. The idea underlying the COSMIC method is that, for many types of software, most of the development efforts is devoted to handling data movements. In this chapter, we analyse various aspects of the use of COSMIC to measure distributed applications in cloud environments. We take into account three distinct provision models of the cloud computing stack, namely, the Infrastructure as a Service (IaaS), Platform as a Service (PaaS), and Software as a Service (SaaS), in which the cloud vendors, customers, and the applications themselves play a different role and have different responsibilities. Moreover, we consider some aspects being formally classified as non-functional requirements (e.g. scalability, reliability), but particularly critical in the field of cloud computing