Patent ID: 7240171

Claim:
A storage medium tangibly embodying a program of machine-readable instructions executable by a digital processing apparatus to perform a method for ensuring consistency of a group, the method comprising the following operations: receiving a first list, wherein the first list identifies a first group of objects; for each object identified in the first group, gathering a value of an attribute corresponding with the object, so each gathered attribute value is associated with a corresponding object identified in the first group; storing, at a time t 1 , the first list that identifies the first group of objects, and the value of the attribute corresponding with each object in the first group of objects, to create a first snapshot of the first list that identifies the first group of objects and the attribute value corresponding with each object in the first group of objects; after at least part of a task is performed, receiving a second list, wherein the second list identifies a second group of objects, and receiving, for each object identified in the second group, a value of the attribute corresponding with the object, so each received attribute value is associated with a corresponding object identified in the second group; storing, at a time t 2 , the second list that identifies the second group of objects, and the value of the attribute corresponding with each object in the second group of objects, to create a second snapshot of the second list that identifies the second group of objects and the attribute value corresponding with each object in the second group of objects; and comparing the first snapshot with the second snapshot.