Linked by Eugenia Loli on Mon 9th Oct 2006 01:31 UTC
QNX Most people haven't heard of QNX Software, though they've likely come in contact with it. The real-time operating system is used where software failure can lead to catastrophic consequences, even death - from high-speed trains to air traffic control towers to highway toll systems. It's also used in more than 100 different types of cars on the road.
Permalink for comment 169903
To read all comments associated with this story, please click here.
RE: air-traffic is not on QNX
by djst on Mon 9th Oct 2006 09:28 UTC in reply to "air-traffic is not on QNX"
Member since:

I work on Air Traffic systems and have since 1995. Standard Air Force and FAA equipment. Systems run on a mix of Windows 3.11, DOS, Windows NT 4, Windows 2000, Windows 95, AIX, and Solaris (various versions). That's the recorder systems, switching systems, radar mosaic (terminal and air route), and so forth. I know of no air traffic system that runs QNX, unless it's on ROM for a specific functionality inside modems, monitors or some such. All of the primary systems are PC-controlled.

The operating systems you mention are not real time operating systems (RTOS). A RTOS can guarantee that a calculation/operation is completed within a specific time limit. Failure to complete the calculation within that time limit in a RTOS is considered a system failure, something that can have catastrophic effects.

A RTOS is often confused with fast systems (see other reply to your post) when in fact it does not have to be fast at all. The important thing is that the RTOS can guarantee that it will complete its operations in time. The fact that a deadline can be set to 50 nanoseconds or even a whole minute is not relevant.

Windows 3.11, 95, NT4, etc. are general purpose operating systems. They lack the mechanisms that allow them to guarantee that deadlines will be met. They are not necessarily slow systems, but the execution time for a calculation can vary greatly depending on (among other things) the system load.

Edited 2006-10-09 09:28

Reply Parent Score: 5