Software diversity metrics and measurements

In this paper, we deene and formalize the concept of software diversity, which characterizes N-Version Software (NVS) from four diierent points of view that are designated as: structural diversity, fault diversity, tough-spot diversity, and failure diversity. Our goals are to nd a way to quantify software diversity and to investigate the measurements which can be applied during the life cycle of NVS to gain conndence that operation will be dependable when NVS is actually employed. The versions from a six-language N-Version Programming project for fault-tolerant ight control software were used in the software diversity measurement .