Duncan Grisby's Ph.D. Research

Existing window systems are large monolithic entities which require significant resources to run. Most systems, such as Windows and the Mac OS, have no concept of distribution. The X window system allows remote displays, but splits the functionality into two large components -- the server at the endpoint, and the X library (and associated toolkits) at the application server.

At present, there is a move towards simple, low-power endpoints, or `Network Computers'. Such devices may be incapable of running a complex window system such as X. One solution is to use a very simple protocol, such as VNC, which simply encodes pixel updates in a compressed manner. This has the disadvantage that it requires substantial network capacity, and low network latency, to be useful. It is therefore only really suitable for local area networks.

My research was focussed on a new distributed adaptive window system, named DAWS, based upon CORBA objects. Every component of the system is a CORBA object, and so may potentially reside on a remote machine. This provides the framework for a very flexible system which may be configured to make the best use of available processing and network resources. If, for example, a user with a low-power network computer wished to run an application remotely across a wide area network, the system could be configured to perform most of the processing at a server on the user's local area network, thus requiring that only a small amount of traffic was sent across the wide area network. Much more traffic (such as VNC-style compressed pixel data) would be sent between the local server and the user's network computer.

Object migration

The system is made even more flexible by providing a means for CORBA objects to move from location to location at run time. This is useful both for load balancing, and so that users may be followed as they move from place to place. Most CORBA ORBs have little or no support for moving objects, so I implemented what I required for omniORB, a free C++ ORB.


If you're really keen, you can download my PhD dissertation, as gzipped PostScript(440K).
I did my PhD in the Laboratory for Communications Engineering.

You may wish to go to my rather unexciting home page.

Duncan Grisby <duncan@grisby.org>.