Grid Services Extend Web Services @ WSJ

Grid Services Extend Web Services @ WSJ: "Distributed systems research has a rich literature where virtualization of resources and objects is a common solution to many problems. This virtualization results in a 'transparency.' Nine of these show up again and again. They are used with respect to accessing a remote service or object. Usually the intent is that the programmer/user need not know or deal with something, but can if they want to. The transparencies are:

Access: The mechanism used for a local procedure call is the same as for a remote call. Many have argued that this is a special case on location transparency.
Location: The caller need not know where the object is located, California or Virginia - it makes no difference.
Failure: If the object fails the caller is unaware. Somehow the requested service or function is performed, the object is restarted, or whatever is needed happens.
Heterogeneity: Architecture and OS boundaries are invisible. However, objects cannot migrate without limitation. At a bare minimum communication with objects on other architectures requires no data coercion.
Migration: The caller need not know whether an object has moved since they last communicated with it.
Replication: Is there one object or many objects behind the name? The caller need not know or deal with coherence issues.
Concurrency: Are there other concurrent users of an object? The caller need not be aware of them.
Scaling: An increase or decrease in the number of servers requires no change in the software. Naturally, performance may vary.
Behavioral: Is it live or not? Whether an actual object or a simulation of the object is used is irrelevant. For example, am I talking to a host object, or a virtual host objec"