grid computing in many cases the grid is made up of heterogeneous set of computers (rather than all computers being the sameand may be geographically dispersed these computers may be comprised of both physical computers and virtual machines virtual machine is piece of software that emulates whole computer and runs on some underlying hardware that is shared with other virtual machines each virtual machine thinks it is the only computer on the hardwarehowever the virtual machines all share the resources of the physical computer multiple virtual machines can thus run simultaneously on the same physical computer each virtual machine provides its own virtual hardwareincluding cpusmemoryhard drivesnetwork interfaces and other devices the virtual hardware is then mapped to the real hardware on the physical machine which saves costs by reducing the need for physical hardware systems along with the associated maintenance costsas well as reducing the power and cooling demands of multiple computers within gridsoftware is used to manage the grid nodes and to submit jobs to those nodes such software will receive the jobs to perform (programs to run and information about the environment such as libraries to usefrom clients of the grid these jobs are typically added to job queue before job scheduler submits them to node within the grid when any results are generated by the job they are collected from the node and returned to the client this is illustrated below