Scientific workflows are a powerful programming technique for specifying complex computations using a number of otherwise independent components. When used in a Grid environment, it is possible to build powerful “virtual applications” across multiple distributed and heterogeneous resources. Whilst toolkits such as Globus virtualize many system attributes, and thus make it easier to span different organizations, inconsistent security policies and resource heterogeneity can limit the applicability of workflow techniques.
In earlier work, we have described a novel run time environment, GriddLeS, that
supports flexible communication patterns between workflow components. GriddLeS
abstracts IO operations, such that applications are given the illusion of
operating on a local file system, whilst in fact they send and receive data
between components. In this paper, we describe how GriddLeS assists in resolving
some of the issues that arise due to heterogeneity in security policies and
system architectures in a Grid environment. We illustrate the solution using a
real world scientific workflow for climate modeling, and demonstrate a system
that spans multiple conflicting security domains with heterogeneous resources.