Checkpointing of parallel applications can be used as the core technology to provide process migration. Both, checkpointing and migration, are an important issue for parallel applications on networks of workstations. The CoCheck environment which we present in this paper introduces a new approach to provide checkpointing and migration for parallel applications. In difference to existing systems CoCheck rather sits on top of the message passing library than inside and achieves consistency at a level above the message passing system. It uses an existing single process checkpointer which is available for a wide range of systems. Hence, CoCheck can be easily adapted to both, different message passing systems and new machines.

Parallel Virtual Machine (PVM) is a widely-used software system that allows a heterogeneous set of parallel and serial UNIX-based computers to be programmed as a single distributed-memory parallel machine. In this paper, an extension to PVM to support dynamic process migration is presented. Support for migration is important in general-purpose workstation environments since it allows parallel computations to co-exist with other applications, using idle-cycles as they become available and off-loading from workstations when they are no longer free. A description and evaluation of the design and implementation of the prototype Migratable PVM system is presented together with some performance results. 1 Introduction PVM [1, 2, 3] is a software system that allows a heterogeneous network of parallel and serial computers to be programmed as a single computational resource. This resource appears to the application programmer as a potentially large distributed-memory virtual computer. Such a s...

this paper. We use the term job to indicate the largest entity of execution (program) consisting of one (serial program) or more cooperating tasks (parallel program).