Microsoft® Windows Server® 2008: Implementation and Administration

1.2. System Overview

Windows Server is an example of a preemptive, multitasked, multithreaded operating system. The term preemptive means that the Windows operating system can switch the order of tasks held in memory based on a set of scheduling policies and priorities, a process commonly referred to as context switching. Windows can perform a context switch because it recognizes that a process has ended, that a process is blocked by a shared resource, or that the process has been switched to another processor. This behavior (which is a software version of a system interrupt) is performed by the kernel, and is different from a system in which tasks are scheduled through time sharing or through a system of hardware interrupts. There are many ...