lows a computer to seemingly be performing more than one task at any given time. Processors cannot work on many things at once, but operating systems can be designed in such a way that they handle many tasks at one time, and share the processor. Windows NT queues up tasks, giving each one a priority level. NT has 32 different priority levels (0 - 31). Then, based on that information (in addition to other information), the operating system does some of task 1, some of task 2, some of task 3, and some of task 1 again. It swaps each task in and out of the processor, giving the illusion that the computer is doing many things at the same time. Windows NT also does a very good job at isolating tasks in memory, so that if a task hangs or otherwise becomes inoperable, you can kill it easily and quickly, somewhat like UNIX. Programs are not allowed to use memory areas which the OS is using, and are also not allowed to use memory areas which other programs are using. This reduces the chance that a crashed application will affect the integrity of the operating system or other programs. Symmetric Multiprocessing Support Using a technique called Symmetrical Multiprocessing (SMP), Windows NT is capable of utilizing more than one processor on the same system. Unlike Asymmetrical Multiprocessing, which assigns different types of tasks to different processors, Symmetrical Multiprocessing is capable of assigning any task to any processor on the system. This has the end result of using each processor to its fullest extent. Out of the box, Windows NT will support two processors in Workstation form, and four processors in Server form (eight for NT Server Enterprise Edition). Some special versions of Windows NT have the capability to support up to 32 processors. This was originally the upper limit that Windows NT was architecturally designed to support. Microsoft does not officially support NT ...
