Getting Started with QNX Neutrino - QNX Software Systems

© 2009, QNX Software Systems GmbH & Co. KG. QNX 4 and Neutrino
QNX 4 and Neutrino
In this appendix, we’ll take a look at QSS’s previous operating system, QNX 4, and
see how it compares to Neutrino. This appendix will mainly be of interest if you are a
current QNX 4 customer and want to see:
• What’s so great about Neutrino?
• How hard will it be when I port to Neutrino?
Or you may be developing for, or porting to, both operating systems.
Similarities
Let’s first start with how the two generations of operating systems are similar:
• message passing is at the heart of the architecture
• network-distributed message passing
• realtime
• microkernel architecture
• processes are memory-protected
• POSIX compatibility
• relatively simple “device driver” model
• embeddable
Note that while some of the basic features listed above are indeed similar, in general
Neutrino has extended the support. For example, Neutrino has more POSIX support
than QNX 4, simply because a large number of the POSIX specifications were still in
draft status when QNX 4 was released. While less of them are in draft status as of
Neutrino’s release, there are still more new drafts being released as this book is
written. It’s a never-ending game of catch-up.
Improvements
Now that you’ve seen what’s the same about the two generations of OS, let’s look at
where Neutrino has improved functionality over QNX 4:
• more POSIX standards supported
• more embeddable
• kernel is more readily customizable for a variety of hardware platforms
• thread support
• simpler device driver model
April 30, 2009 Appendix: A • QNX 4 to Neutrino 287