19-10-2012, 04:56 PM
Introduction to Grid Computing
Grid1.ppt (Size: 575 KB / Downloads: 134)
What is a Grid?
Many definitions exist in the literature
Early defs: Foster and Kesselman, 1998
“A computational grid is a hardware and software infrastructure that provides dependable, consistent, pervasive, and inexpensive access to high-end computational facilities”
Kleinrock 1969:
“We will probably see the spread of ‘computer utilities’, which, like present electric and telephone utilities, will service individual homes and offices across the country.”
Cluster computing
Idea: put some PCs together and get them to communicate
Cheaper to build than a mainframe supercomputer
Different sizes of clusters
Scalable – can grow a cluster by adding more PCs
Peer-to-Peer computing
Connect to other computers
Can access files from any computer on the network
Allows data sharing without going through central server
Decentralized approach also useful for Grid
Internet computing
Idea: many idle PCs on the Internet
Can perform other computations while not being used
“Cycle scavenging” – rely on getting free time on other people’s computers
Example: SETI@home
What are advantages/disadvantages of cycle scavenging?
Distributed Supercomputing
Idea: aggregate computational resources to tackle problems that cannot be solved by a single system
Examples: climate modeling, computational chemistry
Challenges include:
Scheduling scarce and expensive resources
Scalability of protocols and algorithms
Maintaining high levels of performance across heterogeneous systems
High-throughput computing
Schedule large numbers of independent tasks
Goal: exploit unused CPU cycles (e.g., from idle workstations)
Unlike distributed computing, tasks loosely coupled
Examples: parameter studies, cryptographic problems
On-demand computing
Use Grid capabilities to meet short-term requirements for resources that cannot conveniently be located locally
Unlike distributed computing, driven by cost-performance concerns rather than absolute performance
Dispatch expensive or specialized computations to remote servers