The QNX Neutrino microkernel offers superior real-time response. With features like multitasking, threads, priority-driven preemptive scheduling, synchronization, and fast context switching (0.55 µsec on a Pentium III), the RTOS provides serious realtime performance. By real time, we mean that a command will be executed in the time it is expected e.g. immediately (but its priority can also be scheduled by the programmer), no matter what the conditions are. At first reading, this sounds great. But things are not so great when you have 1-2 videos playing and at the same time you are using the web or the doing a resource intensive search on your hard disk. Real Time is the absolute bless for embedded system purposes, but not so great for the ultimate desktop experience. When you only have one application running, QNX is incredibly speedy and responsive, add one-two more intensive apps, and the system becomes unnaturally slow and unresponsive (when compared to the behaviour of other OSes under similar circumstances). This is not due to multitasking reasons (which is implemented and works fine), but due to the real time nature of the kernel being more suitable for embedded purposes.
QNX and Photon is written in C, and the APIs are also C-based. There are three (!) third party efforts to add C++ bindings to Photon, but all these efforts are still far from finished.
Additionally, when developing a commercial product for QNX RtP, you should pay a license fee to QNX Software Systems before you will be allowed to release your product to the market. This may sound a bit restrictive to most people, but it is a fairly common practice in the embedded world. And we should not forget that QSSL is not focusing on the desktop market almost at all. QNX RtP is serving as the self hosted development platform for QNX-based internet appliances and other QNX embedded applications.
Other strong points of QNX is that it is POSIX certified, which means that people familiar with the Unix model will feel like home. There is even a port of the BASH shell. Massively scalable transparent networking is another of its strong points. More information here.
In QNX RtP 6.2 you will find many bug fixes and some new drivers. However, I somewhat got the feeling from the new version that QSSL is moving even more far away from a "desktop QNX." A handfull of previously familiar apps could not be found in 6.2 (or at least, I could not find them). I lost track of phPDF, Real Player, phAB (the excellent RAD program), Java support, Renderware (3D engine), and even the 3-4 classic games that were included in previous versions!
I was somewhat dissapointed that drag-n-drop is still not supported Photon-wide, the DVD issue was still not resolved after 1.5 years, and 3D support seems to still only work with Glide and Voodoo3. A better performed filesystem would be welcomed too.
Version 6.2 does not bring a whole lot of new things over 6.1PatchA. The OS is, however, more polished and some fixes and new drivers are there, along with better printing support, but also a lot of things are now missing. There are no radical changes to QNX RtP. It is a fun ride, but without the QNXStart software repository coming back online soon and some more effort by QNX Software Systems on the desktop side of the OS, RtP's further success feels a bit questionable.
If you have tried QNX RtP in the past, you already have a taste of the OS. If you have never tried it, I sincerely urge you to do so. It is a good experience on a stable system. And if you are a professional in the embedded systems field, it is definetely a must-see.
Resources:
BeNews Preview of RtP 6.0 (Aug 2000)
QNXZone (qnx news)
Installation: 8/10
Hardware Support: 7.5/10
Ease of use: 8/10
Features: 8.5/10
Speed: 8/10 (UI responsiveness, latency, throughput)
Overall: 8 / 10
- "Installation, Desktop"
- "The Internals, What is missing, Epilogue"
