Grid computing basics

Grids are usually computer clusters, but more focused on throughput like a

computing utility rather than running fewer, tightly-coupled jobs. Often, grids will

incorporate heterogeneous collections of computers, possibly distributed

geographically, sometimes administered by unrelated organizations.

Grid computing is optimized for workloads which consist of many independent jobs

or packets of work, which do not have to share data between the jobs during the

computation process. Grids serve to manage the allocation of jobs to computers

which will perform the work independently of the rest of the grid cluster. Resources

such as storage may be shared by all the nodes, but intermediate results of one job

do not affect other jobs in progress on other nodes of the grid.

An example of a very large grid is the Folding@home project. It is analyzing data that

is used by researchers to find cures for diseases such as Alzheimer's and cancer.

Another large project is the SETI@home project, which may be the largest distributed

grid in existence. It uses approximately three million home computers all over the

world to analyze data from the Arecibo Observatory radiotelescope, searching for

evidence of extraterrestrial intelligence. In both of these cases, there is no inter-node

communication or shared storage. Individual nodes connect to a main, central

location to retrieve a small processing job. They then perform the computation and

return the result to the central server. In the case of the @home projects, the software

is generally run when the computer is otherwise idle. U of C Berkley has developed an

open source application BOINC to allow individual users to contribute to the above

and other projects such as lhc@home (Large Hadron Collider) from a single manager

which can then be set to allocate a percentage of idle time to each of the projects a

node is signed up for. The Software can be downloaded and a project list can be

found here BOINC

The grid setup means that the nodes can take however many jobs they are able to

process in one session and then return the results and acquire a new job from a

central project server.