| This thesis explores computation mobility. We view mobility, the selection of an execution environment, as an attribute of a computation. To capture this attribute, we introduce a novel programming abstraction, which we call a mobility attribute, that specifies where computations should occur within a distributed system. Programmers dynamically bind mobility attributes to program components, nonempty sets of functions and their state. Once bound to a component, mobility attributes apply prior to each execution of that component. For example, a mobility attribute can specify that a computation should be collocated with an invoker. When a component bound to that mobility attribute receives an invocation it moves to the invoker's location before executing.;Mobility attributes are the primitives that form MAGE, a new programming model that allows a programmer runtime control over the location of a program's components. This control can improve the program's robustness or its runtime efficiency by co-locating components and resources. To illustrate the utility of MAGE, this thesis presents the design and implementation of the MAGE programming model in a Java library that extends Java's RMI to support mobility attributes. ii... |
