Process migration: a generalized approach using a virtualizing operating system

Process migration has been used to perform specialized tasks, such as load sharing and checkpoint/restarting long running applications. Implementation typically consists of modifications to existing applications and the creation of specialized support systems, which limit the applicability of the methodology. Off the shelf applications have not benefited from process migration technologies, mainly due to the lack of an effective generalized methodology and facility. The benefits of process migration include mobility, checkpointing, relocation, scheduling and on the fly maintenance. This paper shows how regular shrink-wrapped applications can be migrated. The approach to migration is to virtualize the application by injecting functionality into running applications and operating systems. Using this scheme, we separate the physical resource bindings of the application and replace it with virtual bindings. This technique is referred to as virtualization. We have developed a virtualizing operating system (vOS), residing on top of Windows 2000 that injects stock applications with the virtualizing software. It coordinates activities across multiple platforms providing new functionality to the existing applications. The vOS makes it possible to build communities of systems that cooperate to run applications and share resources non-intrusively while retaining application binary compatibility.