Research On The Core Technology Of Grid Computing Based On OGSA

With the development of IT technologies, more and more people focus on the issue of providing a flexible, secure, coordinated resource sharing among dynamic collections of individuals, institutions, and resources - so called virtual organization. Current distributed computing technologies, such as p2p, COM/DCOM, CORBA, DCE, J2EE, etc, can't adapt to the resource variety, nor can they provide the flexibility and controlling mechanism of resource sharing to setup virtual organizations, as a whole. Open Grid Service Architecture is proposed to address the challenge, which offers a novel distributed computing mode to provide a flexible, fair mechanism to utilize and share resources in the dynamic extensible virtual organizations.Based on the concepts and technologies of Grid and web service, OGSA defines a unified exposed service semantics, the Grid Service. A Grid Service is an enhanced Web Service. In OGSA grid everything is encapsulated as Grid Service and the Grid becomes the set of grid services. Using WDSL and related open specifications. Open Grid Service Infrastructure defines the standard mechanism for creating, naming, and discovering transient Grid service instances, providing location transparency and multiple protocol bindings for service instances and supporting integration with underlying native platform facilities. It also defines interfaces and associated conventions, mechanisms required for creating composing sophisticated distributed systems, including lifetime management, change management, and notification.Now, Globus Toolkit Versions is the main reference implementation of OGSA, which provides the core service for security, information discovery, data management, communication, error detection, portability and so on. The main components includes Grid resource allocation and manager GRAM, which provides secure and reliable service creation and management; Monitoring and Discovery Service MDS provides information discovery through soft-state registering, data modeling and partial registering; Grid Security Infrastructure GSI supports single-logon, delegation and credential projection; other services such as data management are also included.Based on OGSA, the thesis studies a kind of important resources in grid environment, the devices and the issue of its seamless access. Combining with the author's develop experience of iHome project cooperating with SVA, We adopt the concept used in OSGi for pervasive computing, and propose adistributed Grid device system, extending the device services to Grid device services. The author also studies the practical solution for Telemedicine system based on the suggested grid device system. The following is the main work and contribution of the author:1.Analyses in detail the principles and frame of OGSA and the specification of Grid Service Infrastructure in OGS1;2.Extends the concept of pervasive computing to Grid, so that the flexible access of device is not limited to gateways;3.Proposes a OGSA based distributed Grid device system, adopting the basic principle of OSGi, with the grid driver services taking charge of hardware variety and the grid device services providing the uniform management and service invoking of devices.4.Designs and partly implements a remote telemedicine system.