Software Sustainability in the Age of Everything as a Service

The need for acknowledging and managing sustainability as an essential quality of software systems has been steadily increasing over the past few years, in part as a reaction to the implications of ``software eating the world\u27\u27. Especially the widespread adoption of the Everything as a Service (*aaS) model of delivering software and (virtualized) hardware through cloud computing has put two sustainability dimensions upfront and center. On the one hand, services must be sustainable on a technical level by ensuring continuity of operations for both providers and consumers despite, or even better, while taking into account their evolution. On the other hand, the prosuming of services must also be financially sustainable for the involved stakeholders

The Influence of Green Strategies Design onto Quality Requirements Prioritization

[Context and Motivation] Modern society is facing important challenges that are critical to improve its environmental performance. The literature reports on many green strategies aimed at reducing energy consumption. However, little research has been carried out so far on including green strategies in software design. [Question/problem] In this paper, we investigate how green software strategies can contribute to, and influence, quality requirements prioritization performed iteratively throughout a service-oriented software design process. [Methodology] In collaboration with a Dutch industry partner, an empirical study was carried out with 19 student teams playing the role of software designers, who completed the design of a real-life project through 7 weekly deliverables. [Principle ideas/results] We identified a list of quality requirements (QRs) that were considered by the teams as part of their architectural decisions when green strategies were introduced. By analyzing relations between QRs and green strategies, our study confirms usability as the most used QR for addressing green strategies that allow to create people awareness. Qualities like reliability, performance, interoperability, scalability and availability emerged as the most relevant for addressing service-awareness green strategies. [Contribution] If used at the beginning of a green software project, our results help including the most relevant QRs for addressing those green software strategies that are e.g. the most domain-generic (like increase carbon footprint awareness, paperless service provisioning, virtualization)

Aligning economic impact with environmental benefits: a green strategy model

To achieve lower energy consumption many green strategies (e.g. virtualize applications and consolidate them on shared server machines, or optimize the usage of the private cloud by opening up to external consumers) have been discussed. In practice, however, the major incentive for a company to go green is reducing costs. While green strategies often focus on technical and environmental issues, they hardly address the economic impact that they may bring. If green strategies do not lead to an explicit (and significant) reduction of costs (hence increase in revenues) they are nice but not part of the business strategy of the company. In this paper we propose a green strategy model that provides decision makers with the information needed to decide on whether to take green strategies and eventually how to align them with their business strategies. This model provides a means to codify green strategies in such a way that the link between green strategies, their economic impact and green goals becomes explicit. We applied the model in a case study to codify 132 green actions collected from Dutch data centers. This exercise further confirmed the advantage of using the proposed model and helped us identifying future improvements. © 2012 IEEE

Requirements engineering aspects for sustainable eLearning systems

Sustainability in software engineering is about (1) continued functionality and maintainability in changing circumstances, and (2) functionality's effect on the surrounded environment, economic and people. Frequent changes of software requirements negatively affect sustainability of software systems. To reduce the number of requirements' changes and improve sustainability, sustainability requirements have to be considered from the beginning of the requirements engineering stage of software development. Sustainability in requirements engineering has five dimensions including individual, social, technical, economic and environmental dimensions. Most of the existing work analysed only one or two dimensions and ignore the interrelated effects among other dimensions. To address this issue, we selected eLearning systems because they provide comprehensive example to study. This thesis focuses on analysing sustainability requirements of eLearning systems with regard to the five sustainability dimensions. The following studies were performed: (1) identifying theoretically the sustainability requirements of eLearning systems, (2) investigating empirically the sustainability of eLearning systems, (3) constructing a methodology for the analysis and evaluation of sustainability requirements on eLearning systems, and (4) evaluating the constructed methodology. To the best of our knowledge, this is the first research conducted to investigate sustainability requirements of eLearning systems covering the five sustainability dimensions. Our findings highlighted that (1) technical, economic and environmental sustainability requirements are similar to other software domains, where individual and social sustainability requirements are specific for the domain of eLearning systems, (2) individual and social sustainability requirements need to be carefully considered and analysed together because of the strong correlation, and (3) culture and gender diversity play an important role for sustainability requirements. On this basis, we developed a framework for analysing sustainability requirements of software systems as well as a web-based tool SuSoftPro (the name stands from Software Sustainability Profiling) that allows requirements engineers to: investigate sustainability of software systems based on the systems' requirements, analyse the sustainability dimensions of software systems, measure the sustainability of each individual requirement, visualise analysis results to support decision making towards high-quality software, involve stakeholders to rate their requirements for one or more of the five sustainability dimensions, and manage requirement and stakeholder details easily. We evaluated the SuSoftPro framework through case studies, comparative evaluation and a quantitative questionnaire. Our framework successfully provides a comprehensive view of analysing sustainability requirements to improve the attention to sustainability and allow practitioners to develop sustainable software

Creating Environmental Awareness in Service Oriented Software Engineering

Carbon emission of IT is an issue. ICT energy consumption is expected to grow by 73% (instead of the originally targeted 26%) until 2020, and the service sector alone counts for 70% of the European economy. Energy consumption is a combination of what we use, and how we use it. Most green initiatives look at what types of devices do consume energy, and try to optimize their up-time as such. Few initiatives, though, measure how do software systems actually use these devices, with the goal of optimizing consumption of devices and computing resources. Basic research is needed to address this software optimization problem. The proposed approach is to make visible the environmental impact of software services by measuring it. In this way, we will become aware of the amount of energy needed by our software, and hence learn how to target software optimization where it is mostly needed. As a first step in this direction, in this paper we define three main problem areas to realize green service-based applications, and propose a service-oriented approach to address them. Thanks to that we can bring clarity in what entails managing and developing green software according to environmental strategies. © 2011 Springer-Verlag