QNX is a real time operating system designed for critical tasks. Developed by QNX Software Systems it has a structure similar to UNIX and is compatible to POSIX. With an API Wrapper it supports software for Linux, the source code was opened by QNX partly. His strengths are the development of software, control of industrial roboters and embedded devices. By the real time ability of QNX the Neutrino Kernel allows with a pentium III the controlled reaction time (interrupt processing) of 0.55 Ã‚Âµ sec in which events can be registered. For comparison purposes: Windows NT 4.0 and other time-sharing operating systems react to events only after approx. 10 ms. The GUI with the name photon was introduced for the first time in version QNX 4.x. Before the window manager was named "QNX Windows" and "X Windows". Among other things the reaction behaviour of the GUI was improved.
,As a microkernel-based OS, QNX is based on the idea of running most of the OS in the form of a number of small tasks, known as servers. This differs from the more traditional monolithic kernel, in which the operating system is a single very large program composed of a huge number of "parts" with special abilities. In the case of QNX, the use of a microkernel allows users (developers) to turn off any functionality they do not require without having to change the OS itself; instead, those servers are simply not run