Stateless Ultra-Thin Clients and their Evaluation.
We proposed the use of network-attached frame buffers to access active
computing sessions from any location. These stateless, fixed-function
consoles run no software and require no administration. All computing
is performed by centralized servers that essentially transmit raw
pixels to desktop consoles. Users are isolated from desktop failures
and can transparently move between consoles.
We developed a methodology to evaluate interactive performance of GUI
and multimedia applications, and we conducted a thorough quantitative
analysis on the Sun Ray implementation of such a system.
We demonstrated that commodity ethernet provides an interactive
experience that is indistinguishable from traditional desktops, even
for highly interactive 3D video games. In fact, most applications run
well over DSL or cable modems to the home. This work establishes the
viability of centralized application/computation service providers not
only for the workplace, but also for the home and may have a
potentially large impact on our future computng environments.
Compute capsules.
To support computational service on a globally distributed set of
machines, we restructured operating systems using a new abstraction
called a compute capsule. Capsules provide a private, virtualized,
machine-independent interface to system resources, and they
encapsulate all the state of a user's active computing session.
Capsules can migrate between machines or reside off-line in stable
storage. Hosts in the system merely serve as caches for active
computations. Because of these properties, capsules offer an elegant
solution to a variety of problems: scaling to unlimited logins,
dynamic load balancing, system availability and on-line maintenance,
application-independent checkpoint/resume, mobility, and remote
administration. Capsules are isolated for privacy, customizable for
flexibility, and schedulable for performance.
We have demonstrated that it is feasible to extend COTS operating
systems with this abstraction, and our prototype can suspend and
resume complete login sessions running standard batch, GUI, and
multimedia applications. For example, we can suspend a window session
(running a web browser, video, Quake, email, calendar, word processor,
spreadsheet, shell windows, etc. all communicating in arbitrary ways),
write its full state to disk, and then resurrect it on a different
machine (including all open files, devices, and IPC channels). The
applications resume as if nothing happened.
Monica Lam (PI)