What is the difference between qnx and linux

Jerry Hicks jerry In sum as I recall , he says 1 There will likely never be a true realtime Linux -- his group is closest to it, and their work consists of kernel patches that sidestep Linux for a small set of facilities, and all the heavy-duty stuff remains in the non-realtime kernel.

It's simply too large and complex. If I've misunderstood any of his points, someone else who read the article please clear things up even better, someone connected with the project who might read this newsgroup. John Perry Pulse Electronics jpe You need to discuss a real project with them with at least semi-real volume forcasts. I don't think this is unreasonable. Personally, I don't think their development tools are overpriced. They are quality tools that pay for themselves quite quickly, i.

Define Unix. Good luck. You will see a wide range of "compatabilities". If you look at how far some of them divert from the "core" QNX is closer than a couple in some areas,. Hell, HP-UX can't guarantee that code written for Unix is a myth, there are more flavours of Unix than I'd care to count, and each requires varyin degrees of work to "port" code.

Each "unix" out there, tries to keep a core that is compatible, but they also keep extensions that are not. The extensions are what gives them a competitive advantage. Now, depending on the intentions of the programmer or development team they may choose to write portable code, or they may choose to use the extensions for a particular "unix" to get the "best" code for that platform.

So, in short, compatability itself can even be a myth. You choose to write compatible code, or platform-specific code. If you want code that is platform-specific across a large number of platforms, then you get used to ifdef HPUX QNX suffers from this as much or as little as any other "unix" out there. Cheers, Camz. It may be outside my experience, but I don't recall us making a contribution of this sort. We do submit bug fixes and diffs though.

In that case I find your point of view hard to understand; the HP-UX kernel was once upon a time based upon 4. Thanks James. They say raw eggs are good for the complexion I should know : Jerry Hicks jerry Thanks for raising the issue.

Well, QNX just went up a couple of notches in my opinion Norm: Any cheap, tawdry thing that'll get me a beer. Just to interject I've been fascinated by this thread about QNX, the kudos and brickbats it gets, and simply amazed that I'd never heard of it prior to the thread.

Sorry if I'm interrupting some serious discussion. Bob L. Java appears to discourage Unix-like interfaces; CGI appears to encourage them I like to think QNX reflects the 'unix' philosophy. I don't know about all that. As a student in a controls and robotics program here at Clemson university, I have not seen too much voraciousness and savagery. Since we qualify for QSSL's educational program they give us their software and manuals free or at minimal cost. The OS comes on 4 floppies including networking.

The gui comes on about 4 with development stuff. You can get a demo floppy which has the OS, Photon, web browser, and some other stuff off their web page www. As far as development tools, I'm happy with the watcom stuff on QNX. The debugger is nicer than any Linux debugger I've seen though it could stand some improvement - like a bigger window : But it has all the nice Turbo C Debugger style features. The bulk of my work right now is on QNX as it is real time control software.

All of the above OSs have their target audience. QNX is my choice for real time work. It lets me get the job done quicker and better with less overhead. I have used RTLinux, and while it is very clever, it is a limited hack when compared to the robustness of QNX which is designed from the ground up for real time work. Actually Dan obviously didn't write that.

I have spoken to the person who did, and I believe that this and a couple of other comments are regretted somewhat, and were to a large extent born out of frustration and some misunderstandings. I also believe that Johnathon will also from here on in become an enthusiastic and loyal proponent of QNX just like many others who frequent this newsgroup now that he has vented his liver and had some of these misunderstandings cleared up.

I think it might have something to do with short-term vs. I think you speak for a lot of us Nick. Personally, I am not doing any hard real-time stuff at the moment mainly soft. But what I am doing requires performance, elegance, and fast development time try knocking up a raw ethernet driver using an FD interface in a couple of days in NT! My 2 cents worth. Geoff Roberts. Cost of manuals and platform licenses was nothing compared to ability to use O.

Support on net for all OS aspects immediate with wide talent base vs. Like iRMX from Intel where we spent thousands on tech support which couldn't compare to Linux newsgroup support. One effort in migrating our code was changing propriatary message passing to Sys V InterProcessCommunication - well worth the effort to get us out from under the propriatary yoke and POSIX compliant.

Now if Linux or whatever platform doesn't meet our needs, moving is no big deal and IPC works great. The O. My condolences for small systems houses that face this. But as a Unix developer and user Linux is a godsend. Where is Java? Why to pay for a Internet suite when a lot of other systems support this for free?

Where are the books about writing device drivers for QNX? XWindows is not usefull for small embedded systems Use the GNU stuff Watcom is one of the best compilers DCOM is not an open standard CORBA is an open standard! It's late Customer orientation is the issue It is even harder because FLEET technology is unpublished and available only for non-disclosure agreement.

A silly approach, IMHO. This will allow them to coexist smoothly using dual-boot. Any system use some specific tricks in drivers. Including all versions of Unix. QNX driver architecture is most elegant I ever heard about. Some package like Willows sure would exist, allowing to recompile Photon apps for X. Probably it would be possible to recompile X for Photon, but this will take much more work.

I guess, QSSL will not do the last, but may be the first, if they will see reasonable demand. Guys, if you would like such feature, please tell to Dan This may be solved someday. Our engineering services team has a proven track record of guiding our customers through safety certification, while ensuring product launch dates are met. Xavier is a senior product and team leader with 15 years of experience in software architecture and development.

By leveraging the latest advances in edge computing, that is, deploying edge gateways to collect and preprocess data from numerous sensors and other devices spread across. When it comes to developing safety-critical systems like industrial equipment, automotive systems and medical devices, avoiding certification is no longer an option, nor is it easy.

Save my name, email, and website in this browser for the next time I comment. March 12, Cybersecurity , ICS Security. Linux QNX safety certification. Pre-Certified Solutions Your choice of real-time operating system RTOS can have an oversized effect on your ability to safety-certify an embedded device. Monolithic OS versus Microkernel OS Although monolithic OS architectures such as Linux are widespread, they provide little or no protection between processes, potentially resulting in priority functions failing to get timely access to the processor.

Both the systems are widely used in large industrial and academic environments and have been in business for over decades. VxWorks is a proprietary software developed by California-based Wind River Systems, the industry-leader specialized in building embedded software for intelligent connected products and systems.

The main difference lies in the architecture — while QNX is based on a message passing architecture, VxWorks lends itself to shared memory architecture. Message passing is fundamental to the kernel design which allows the system to pass information from one task to another or to several others in the system. Shared memory architecture refers to a system which has its own private address space for physically distributed memories.

One of the key differences between the two real-time operating systems is that QNX is a microkernel-based OS whereas VxWorks is a monolithic kernel. A microkernel is like a small operating system that leverages system calls to manage basic services like address space management, thread management, and interprocess communications. It refers to a system which requires a limited set of primitives and minimum software dependency to implement an OS.

A monolithic kernel, on the other hand, manages all the basic services and user-defined services including inter-process communications in a protected kernel space. As a monolithic kernel, VxWorks is self-contained. Every thread or process has its own priority in QNX. Under QNX, all the processes run on a priority-driven preemptive basis meaning the process with the highest priority gets to access the CPU first and the priorities range from 0 to VxWorks, on the other hand, uses only two types of scheduling algorithms, preemptive priority-based and Round-Robin scheduling.

Together they provide a greater degree of control to the users for efficient scheduling. Both are kernel-based real-time operating systems intended for real-time applications that require tasks to be processed and completed as they come in within a pre-defined time constraint, otherwise referred to as deadlines.

Both are in the business for over 25 years and are specialized in developing embedded products and systems, but this is where all the similarities end.

QNX is a microkernel-based real-time operating system which is rather fascinating on its own, thanks to its message passing based architecture which is ideal for making reliable distributed systems. If you have any concerns or complaints relating to the article, please send an email, providing a detailed description of the concern or complaint, to info-contact alibabacloud.

A staff member will contact you within 5 working days. Once verified, infringing content will be removed immediately. The content source of this page is from Internet, which doesn't represent Alibaba Cloud's opinion; products and services mentioned on that page don't have any relationship with Alibaba Cloud.

If the content of the page makes you feel confusing, please write us an email, we will handle the problem within 5 days after receiving your email. If you find any instances of plagiarism from the community, please send an email to: info-contact alibabacloud.