On the usability of grid middleware and security mechanisms.

Usability is an all too often neglected aspect of grid computing, although it is one of the principal factors militating against the widespread uptake of distributed computing. Many resource providers on a grid infrastructure deploy a standard middleware stack and expect users to invoke the default client tools for that middleware stack to access their resources. Unfortunately, many of these middleware client tools have been developed as an afterthought, and are widely considered difficult to use. Such tools typically require a user to interact with a machine, to stage data and launch jobs, and to use digital certificates. Our experience of working with grids over many years has led us to propose a new model of grid interaction, which we call the user-application interaction model. Similar considerations have also led us to develop environments that remove digital certificates from the user's experience, replacing them with familiar username and password authentication credentials. In this paper, we investigate the usability of this interaction model and its security system through a series of tests, which compare the usability of our systems with commonly deployed middleware tools using five usability metrics. Our middleware and security solutions are judged to be more usable than the systems in use by most of today's computational grids.