Parallel computers are operated differently than a normal PC, all users must share the system. Therefore, various operative procedures are in place. Users must understand these concepts and procedures to be able to use the available resources of a system to run a parallel application. A workload manager/job scheduler controls how available hardware resources are distributed among the user requests (jobs).
Users of computing centers typically compete for the expensive HPC resources of cluster systems. HPC resources can be distinguished as
The configuration of the cluster system matters as well: a cluster node can also be a resource that is shared between several users.
A major aspect of job scheduling is to manage these resources in a way that users are treated fairly. Accounting for users or user groups can additionally support this.