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Community Grid for PDA project is developing
the environment supporting ubiquitous accessing to Community Grid
systems from various small wireless devices such as Smartphone. These devices are running the Microsoft
Windows CE or PalmOS and working with traditional desktop
computer.
Universal access
refers to the capability that all users are able to access
information systems (grids) independent of their access device and
their physical capabilities. We address this for Personal Digital
Assistants (PDAs) and generalize it to universal collaboration – the
capability of multiple users to link together over the web with
disparate access modes. Mobile systems are typically slow,
unreliable, and have unpredictable temporal characteristics.
Further, the user interface is clearly limited. The design of
distributed mobile applications needs to identify the
practicalities, reliability, and possibilities of continuous
interaction and integrate synchronous and asynchronous
collaboration.
The Garnet Collaboration system is designed
to support both centralized and peer-to-peer collaboration models
by using a uniform event bus. This event bus is defined in XML
(but implemented with a pure Java solution) and supports both
control messages and events specifying changes in object state.
This is the conventional shared event model of collaboration where
such object state messages ensure that objects are properly shared
between collaborating clients.
A key additional characteristic of Garnet
collaboration system concerns the heterogeneity of clients.
Hand-held devices, mobile phones, as well as conventional desktops
can join in one collaboration session. However, the conventional
GMS is not able to support lightweight clients, such as PDAs
because a lightweight client, mobile clients in most cases, has a
smaller display and slower processor. For the integration, we
propose a new universal collaboration and access architecture,
which we call Garnet Message Service Micro Edition (GMSME). This
supports mobile devices and desktop computers.
GMSME consists of a PDA adaptor, a Hand Held
Message Service (HHMS) protocol, and an API for application
processors, which process messages on the mobile device.
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