A computer's hardware components such as CPU, memory, disk and network I/O, define the resources of a system. They contain certain attributes, such as capacities or speed.

Since the hardware components represent non-shareable resources, the operating system provisions hardware between the processes. The operating system provides system-wide resources and schedule threads for the CPUs.

For this reason, the model considers the overall system, including hardware. The enterprise application potentially doesn't run alone on the system's hardware. Other processes utilize hardware components and thus influence the application's performance. Multiple processes that simultaneously try to access the network will result in poorer responsiveness than running each of them independently.