Editorial: Grid Performability

Grid computing offers many scientific and commercial benefits, but also many technical and organisational challenges. This has led to many research areas in traditional distributed systems directing their efforts on to grid systems. Amongst the challenges for grid computing is the need to provide reliable quality of service to end users. Grid computing promises much for high performance computing but can also suffer from overheads introduced by crossdomain connectivity and extensive middleware, as well as more familiar problems generally associated with distributed systems, such as communication latency and unreliable infrastructure. In this special issue the focus is on grid performability: that is, the joint consideration of performance and dependability. The term ‘performability’ was first introduced by John F. Meyer 25 years ago [1] and was initially focussed on the need for unified measures. Since that time it has become apparent that by considering systems in this way we can achieve greater impact in terms of system effectiveness, efficiency, and adaptability. Research in performability is often carried out in both the performance and dependability fields without overt reference to the other. However, as Tai et al. [2] write: