True, stable multitasking

All applications in Linux run in their own private memory space. This means that a poorly-written application cannot tamper with the memory of another application (or the kernel). If an application does try to access memory it doesn't own, it is immediately halted by the operating system, without disturbing any other process on the system.

The Windows family of operating systems implement this type of protection imperfectly. Even Windows NT, the most protected Microsoft operating system, does not by default enforce as strict a separation between processes, and deliberately allows some ability to tamper with the kernel. This often leads to undesired interactions, which can impair the stability of the system.

In addition, all programs under Linux are preemptively multitasked. This means that the OS handles all scheduling of processes (and kernel threads). No application can hog the resources of the system unless the system administrator specifically defines it as high-priority. This leads to smoother performance and better load balancing.