Log-based Collaborative Infrastructure

Abstract:

Current application-sharing systems support a single architectural mapping for
all collaborations, though different systems support different architectural
mappings. My thesis has identified a new collaborative infrastructure that
supports a wide range of architectural mappings and dynamic mapping changes.
The supported mappings include all of the existing architectural mappings
defined so far including the centralized, replicated, and hybrid mappings. The
thesis shows that a logging approach is sufficient for implementing the
supported mappings and dynamic mapping changes. The logging approach records
messages sent to one incarnation of an object, and replays the recorded
messages to a different incarnation of the object. It uses a new form of
logging, called object-based logging, which models the state of program and
user interface as attributed objects connected by dependencies, and offers the
generality of traditional command-based logging and the efficiency of state
copying. Instead of being bound to a specific I/O protocol such as the X
protocol, it is based on a simple abstract I/O protocol to which specific I/O
protocols must be mapped by client-supplied code. The thesis shows that the new
collaborative infrastructure is composable with client systems representing
various categories of software systems. It also shows, through experiment and a
theoretical model, that the choice of the architectural mapping depends on the
computers used by the collaborators, the speed of the connections between the
computers, the amount of work necessary to process user input, and user
composition changes. It, thus, contradicts the popular belief that the
replicated mapping always gives better performance, and shows the need for
supporting various mapping choices in a system.

Biography:

Goopeel Chung is a postdoctoral research associate in the Department of
Computer Science at the University of North Carolina at Chapel Hill. He
recently defended his Ph.D dissertation at the same university. He received a
B.S. degree in Computer Engineering from the Seoul National University of Korea
and a M.S. in Computer Science from University of North Carolina at Chapel
Hill. His research interests are in collaborative infrastructures, shared
window systems, composability, log-based systems, process migration, user
interface systems, mobile computing, and distributed systems.

################################