How SSI Cluster differ from PVM Cluster?

SSI:

SSI stands for Single System Image which is the simplest way of High Performance Computing, it uses a clustering middleware such as openMosix (http://openmosix.sourceforge.net/). In the SSI cluster, all the member nodes in a Local Area Network collectively deliver performance as single virtual machine.

Advantage:

• Very easy to setup.
• No special hardware and software requirements.
• Applications need not to be recompiled for multicomputing environment.
  

Usage:

Batch processing aaplications such as Backup(tar+zip) for mulitple files, Media Format Conversion for mulitiple files, Content filtering and e-mail virus scanning etc.

PVM:

PVM stands for Parallel Virtual Machine, in which the cluster distributes a single task into crunches and processes them individually over the member nodes of the cluster. However, a major issue with this type of custering is the recompilation of the application with the PVM/MPI (Parallel Virtual Machine/Massge Passing Interface) libraries such as OpenMPI (http://www.open-mpi.org/) or OSCAR (http://oscar.openclustergroup.org/).

Advantage:

• Can distribute a single task requireing higher CPU Throughput into multiple sub-tasks.
• Node job assignment and thread management is taken care by parallely compiled application itself.

Usage:

Applications that require more CPU crunching such as scientific applications, data modelling, weather forecasting etc.