Answers to the Enterprise Architect Magazine Query
1. What is grid architecture?
Let me start off with defining a Grid. However, it seems to me that various researchers have differing views on Grid
computing mostly based on technologies or applications that they are developing and what they envision it to be. So, do
I! My definition is as follows: “Grid is a type of parallel and distributed system that enables the sharing, selection, and
aggregation of services of heterogeneous resources distributed across "multiple" administrative domains based on their
availability, capability, performance, cost, and users' quality-of-service requirements”.
Like any distributed system, Grids need to address various issues and challenges including: security; autonomy;
heterogeneity of resource access interfaces, policies, capability, pricing; data locality, dynamic variation in availability
of resources, and complexity in creation of applications. Therefore, Grid follows a combination of hierarchical and
decentralized architecture for resource management; and a layered architecture for implementation of various services.
2. How is it different from cluster computing? and from single system parallel
A cluster is made up of multiple interconnected independent nodes that co-operatively work together as a single unified
resource. Unlike Grids, cluster resources are owned by a single organisation and they are managed by a centralized
resource management and scheduling system. That means all users of clusters have to go through a centralized system
that manages allocation of resources to application jobs.
Actually, many Grids are constructed by using clusters or traditional parallel systems as their nodes. For example, the
World-Wide Grid, used in evaluating the Gridbus technologies and applications, has many nodes that are clusters,
which are located in organisations such as AIST-Japan, N*Grid Korea, University of Melbourne, and NRC Canada.
Another example of Grid that contains cluster