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QNX: When an OS Really, Really Has to Work

Posted by michael on from the abnormal-termination dept.

An anonymous reader writes "Fortune has this article about how QNX's OS has found a niche and is doing well. Especially after 1996 when Microsoft executives said they would crush them in 2 years. When your software absolutely positively needs to work!"

45 of 514 comments (clear)

  1. Re:um by b0r1s · · Score: 4, Insightful

    You're missing a little ...

    QNX is a great operating system, but it's a much different market. It's not made for PCs, it's made for embedded, real time applications. You'll find QNX in routers, you'll find it in medical devices, and you'll find it in nuclear power plants.

    What you won't find in QNX is USB support, drivers for a Sound Blaster 16, or Accelerated 3D drivers.

    It's a great operating system, but comparing it to things like Windows, Mac OS, Linux, FreeBSD, or even Solaris and AIX are silly. QNX isn't designed to have any frills: it manages resources, incredibly well, and that's it. It doens't do complex scheduling, it doesn't do advanced 3d tricks, and it's not going to do much with the latest firewire hard drives. It will, however, guide a laser over someone's eye for Lasik and other such procedures a thousand times a year without a glitch.

    --
    Mooniacs for iOS and Android
  2. Re:QNX is still around? by $calar · · Score: 4, Informative

    Yes they are around, in fact some more recent news about them came out of the JavaOne conference: http://rcrnews.com/cgi-bin/news.pl?newsId=13840 They are going to be integrating IBMâ(TM)s WebSphere Micro Environment.

  3. Re:A couple things by aggieben · · Score: 5, Insightful

    It isn't the operating system controlling the grinding of lenses or correcting the tilt of the TGV. It is a function of the hardware to do these things. That they report back to some software (which could frankly be run on any embedded OS) which then tells them what to do next is almost irrelevant.

    Ummm...it is the operating system that matters -- the O.S. is the software that controls the hardware. Just like software on a PC can make the hardware do things it ought not do, software can make a precision laser be off by 1/100 of a millimeter, destroying someone's retina in the process.

    --
    Don't become a regular here, you will become retarded. -- Yoda the Retard
  4. QNX rules by CausticWindow · · Score: 5, Informative

    QNX is designed like a modern os should be. It's straigt out of an Operating Systems 101 textbook.

    If only Linux had more of QNX's design niceties and robustness.

    Too bad the Amiga/QNX desktop thing never became a big hit.

    --
    How small a thought it takes to fill a whole life
    1. Re:QNX rules by 73939133 · · Score: 4, Insightful

      Let me second that. I think that's the direction open source operating systems should go.

      Microkernels have gotten a bad reputation because Mach/Hurd, for one reason or another didn't deliver. But that doesn't mean the approach itself is flawed.

      Traditional monolithic kernels like Linux (and UNIX and NT/XP--and don't try pretending that NT/XP is a "microkernel") are appealing for budding operating system projects because it's easy to hack something together quickly. But those architectures don't hold up in the long run. You can see the same in ecology: fast growing, non-native plants often displace native plants quickly, but in the end, they die because they aren't well adapted to the long-term conditions.

      Well, maybe if SCO wins, we can look on the bright side: it will finally get Linux out of its rut and create more opportunities for other kernels. Don't get me wrong: like everybody else, I'd much rather not change from the Linux kernel, but if I do have to change, I don't view it as all bad. (Of course, I don't think SCO has any legal grounds at all, but that is probably not related to whether they can win.)

    2. Re:QNX rules by 73939133 · · Score: 4, Insightful

      what's cleaner and more efficient, a single program or 10 different ones passing messages to each other?

      10 different ones passing messages to each other are clearly cleaner and often more efficient as well. It's the UNIX way. I mean, do you run one command line interface that has all programs linked into it, or do you run a command line shell that invokes programs as separate processes?

      The detailed Mach approach itself is broken--far too complex and messy. But you can view Plan 9 as a kind of "microkernel"; that would be a UNIX-style "microkernel". And, of course, QNX is successful as well. The original Amiga OS was a kind of microkernel and worked like a charm.

      Note that you can't compare Linux to the original UNIX design. The original UNIX design was kept religiously simple: one file system, a few machine types, etc. Linux, on the other hand, has zillions of modules and features.

      So far, it didn't work for any real systems.

      It has worked in plenty of real systems. But kludgy monolithic kernels simply have an easier time to attract developers initially--that's why systems like Linux and Windows have managed to grab a lot of market share in the OS area.

    3. Re:QNX rules by CoolGuySteve · · Score: 5, Insightful

      I question the validity of blindly praising microkernels.

      A lot of the decision depends on the architecture involved. I hope someone more knowledgable than myself will comment on this, but as far as I know, the reason BeOS started to implement networking into the main kernel instead of making it a microkernel "server" was because the x86 architecture is much slower in switching between sub-functions than the PowerPC was (I've read 10 times slower but can't remember the source).

      The two monolithic operating systems you criticize are both i386-centric, so a true microkernel probably wouldn't be such a hot idea.

      QNX's design is great for certain applications but not all. I looked into it for an intel based SMP homebrewed but critical (as in the systems behind it cost over $1 million) firewall and decided a more traditional i386 operating system would be better.

      I know you're not a culprit here, but being a fanboy for one design approach or another is just bad engineering sense. It's something I see all the time and I'd wish they'd teach a lot more critical thinking skills at the high school level because of it.

    4. Re:QNX rules by 73939133 · · Score: 4, Insightful

      I appreciate QNX as an embedded platform, but I have yet to hear convincing arguments as to how QNX manages to overcome the address translation and additional costs reguarding interprocess communication, with respect to performance.

      Well, first of all, a microkernel architecture doesn't require any address translation or additional overhead at all; there have been microkernels that run without any MMU at all. And QNX seems competitively fast.

      But let's say, just for the sake of argument, there were overhead associated with it. I would rather have a reliable if slower 2.6 or 3.0 kernel now with the features I need than see the 2.4 kernel limp along from bug regression to bug regression.

      Even QNX has faculties for 'lightweight processes' that have independant stacks and a common global data sandbox.

      Which only goes to show what I was saying: a microkernel architecture does not require that every single little OS process runs in a separate address space. In fact, a good design would let you decide on the fly whether to isolate a process (and pay the overhead) or run the process in a global address space.

    5. Re:QNX rules by Pseudonym · · Score: 5, Insightful

      I agree with you that address translation is a problem, however, this is mostly a problem with the x86 architecture. The x86 flushes the TLB on every address space switch. If we had a decent tagged TLB, this wouldn't be a problem. Indeed, it isn't a problem on most architectures that QNX is asked to run on. Repeat until enlightened: Context switching is only expensive on the x86 architecture.

      The "additional costs" for IPC are mostly an illusion, since we're talking about IPC which is tightly integrated with the kernel, not SysV IPC. Yes, it costs to copy memory, but the cost is there in Linux too; it's just a user space -> kernel space copy rather than a user space -> user space copy.

      Having said that, it may be possible to write an OS for which the context switching is much cheaper. L4 uses a neat scheme where a small part of everyone's address space is allocated to other small processes, so context switching only requires a change of segment, rather than a change of address space mapping. IPC is very fast under L4 if you're doing it with a small address space task.

      Why would linux kernel hackers be adding tools like HTTP servers and packet filtering into the kernel, if it was somehow the UNIX way to keep them as seperate processes managed by the kernel?

      I've wondered that myself. I can only conclude that these projects are either experiments which accidentally escaped the lab, or the hackers who wrote them have no sense of sound software engineering principles.


      --
      sub f{($f)=@_;print"$f(q{$f});";}f(q{sub f{($f)=@_;print"$f(q{$f});";}f});
  5. Re:A couple things by wfberg · · Score: 5, Funny

    WinCE a good embedded system? Hmm.. Isn't that the WinCE that is at the heart of PocketPC? The embedded OS that brought blue screens of death (well, ok, depending on your color scheme a light khaki screen of death) to PDAs? Yeah. I trust WinCE to run my heart monitor if I ever end up in an Intensive Care Unit... *cough*

    --
    SCO employee? Check out the bounty
  6. Pronouciation? by hoser · · Score: 4, Interesting

    Kyu-nicks? or Kyu-Enn-Eks?

    --


    hoser: Slashdot reader since 1987.
    1. Re:Pronouciation? by heli0 · · Score: 4, Informative

      1) What is QNX?

      QNX pronounced like "queue nicks" is a commercial operating system that runs on intel processors, mainly the 386, 486, and Pentium, and their clones, such as MD, Nat Semiconductor, Cyrix, and SGS Thompson.

      The simple answer is that QNX is a realtime, microkernel, preemptive, prioritized, message passing, network distributed, multitasking, multiuser, fault tolerant operating system. This is a "true" microkernel, with the largest QNX kernel to date being less than 10K.

      The QNX/Neutrino microkernel is about 32K, but can run standalone, something the QNX4 microkernel cannot. The QNX/Neutrino microkernel + process manager is about 64K, which is half the size of the QNX4 microkernel + process manager, and it does more.

      --
      Whenever the offence inspires less horror than the punishment, the rigour of penal law is obliged to give way...
  7. Re:um by SoSueMe · · Score: 5, Informative

    Here's what you DO get (from the Neutrino page):
    The QNX Momentics Development Suite Non-Commercial (NC) edition gives you a full self-hosted development environment with the QNX Neutrino RTOS, plus tools, device driver kits, a desktop class browser, and more.

    QNX Neutrino RTOS v 6.2.1

    * Symmetric Multiprocessing (SMP)
    * QNX Photon microGUI
    * Hundreds of POSIX, UNIX, and QNX utilities
    * Distributed processing

    Self-hosted C/C++ development environment for x86 & ARM development only. Reference Platform:

    * iPAQ (ARM development target)

    Driver Development Kits (DDKs)

    Libraries and Tools:

    * ANSI C, GCC v2.95x optimizing compiler, GDB 5.x, Binutils 2.10.x

  8. QNX NC by christurkel · · Score: 5, Informative

    You can download a bootable CD from QNX.com that runs "Live", from the CD, so you kick the wheels, so to speak. You can then install it, if you wish.
    The QNX floppy demo was for QNX4, while the CD is QNX 6, a vastly improved OS. The floppy can still be found but its not half the OS that QNX 6 is.
    QNX is POSIX compliant and can run all Unix utilities, Besides the Photon GUI, you can run various window managers. You can run X Windows apps seemlessly rootless using XPhoton. Already Gimp, AbiWord and others have been ported. There are many native apps as well, irc clients, a mozilla and opera port. Worth a try, at least!
    QNX isn't the easiest OS to use (try getting a USB printer to work and you'll find a new definition of pain and suffering) but it is rock solid and fun to geek with.

    --

    CDE open sourced! https://sourceforge.net/projects/cdesktopenv/
  9. I remember using qnx in a Canadian Highschool by Billly+Gates · · Score: 5, Interesting
    Canada's school systems are strange compared to American schools I have previously attented. I have found their computers horrible inadaquite and out of date.

    Anyway I took 2 programming courses in basic and pascal. The labs used some strange Unisys dumb terminals connected to a builky black looking box. Very XT-ish and looked like it was from the early to mid 80's. Anyway it ran a no name OS called QNX. I believe it was powered by a 286 or 6800 with about 4 megs of ram for all 20 students. It had no display but a teletype printer where we would print out our programs. It handled quite well for such a limited server.

    Its Very old and I remember a 1984 copyright that showed up whenever I booted. I had no idea it was a unixlike system.

    It seemed just as fast as a standalone 286 and it had a "$" as the prompt sign with a strange scripting system. I considered it underpowered and old but was supprised by the included gcc, sed, gmake, and other utilities and powerfull scripting. It had some nice api's for 2d graphics displays.

    Anyway 2 years later I wanted to try Unix after playing with NT 4 when after it just came out. I tried Caldera (shudder )Linux and I was supprised that I have been running gnu and unix all long. The shell scripts and everything were identical and I have been using Unix without even knowing it.

    Linux felt quite old without X in the old days( before kde was stable and gnome was around). But I have qnx running on that horribly ancient system to thank.

    --
    http://saveie6.com/
    1. Re:I remember using qnx in a Canadian Highschool by Yaztromo · · Score: 5, Informative

      That would be the Unisys Icon, either series 1 or 2. They were _not_ dumb terminals however -- the Series 2 used an 80186 (you read that correctly) with 1MB of RAM. The "bulky black box" was the storage system (it had the hard disks and floppy drives) and handled network control. I don't recall what was in the series 1 hardware wise, but it was similar.

      The systems used to be popular in Canadian schools because the OS was developed in Canada, as were most of the tools and applications (which were primarily by Watcom). Plus students generally weren't going to be able to install whatever gunk they brought from their DOS machines at home, nor were DOS based virii any sort of threat to these systems. They were easy to manage and maintain, and were good for teaching programming basics.

      Do you prefer todays alternative of brainwashing students in The Microsoft Way(tm)?

      Yaz.

  10. Re:Inaccurate microkernel claims? by be-fan · · Score: 5, Informative

    NT is hardly a microkernel. A microkernel, according to strict definitions, doesn't include anything like drivers, paging or the filesystem. QNX fits this definition --- the filesystem runs in userspace, and even drivers run as seperate processes that communicate via message passing. In Win2k and WinXP, almost everything runs in kernel space. Heck, in the next version, rumor has it that large parts of SQL and the .NET runtime are going in kernel space! And OS X isn't a microkernel either. It uses Mach, but the BSD server runs in kernel space, and message passing between the two has been replaced by procedure calls.

    --
    A deep unwavering belief is a sure sign you're missing something...
  11. I read slashdot using QNX by leighklotz · · Score: 4, Funny

    I read Slashdot using QNX, on an Audrey. I almost bought another one at a garage sale today for $20, but it had no power supply. Plus the keyboard was Lime.

  12. Re:um by imnoteddy · · Score: 5, Informative
    What you won't find in QNX is USB support

    Sorry, wrong. QNX USB support.

    --
    No electrons were harmed creating this post, though some may have been subjected to electrical and/or magnetic fields.
  13. QNX Floppy Challenge by hendridm · · Score: 4, Informative

    If you haven't taken the challenge yet, it's pretty cool. You can get it here too.

  14. Interesting? by cgenman · · Score: 5, Informative

    I'm trying not to comment on this, but as two people modded it "interesting," obviously this fallacy needs to be shot down. While true for PDA's, which is obviously what ObviousGuy has experience with, it is not at all true for many real embedded systems.

    QNX is for those times when "Good enough" isn't good enough. An associate of mine used to run the network for a major medical responce company. They used to count downtime in the number of people dead due directly to the lack of a network. If you accidentally pulled a plug on the way to lunch, 4 people would be dead because of you.

    Their uptime target was 24-7-365-20. There was no such thing as "Good Enough."

    Ideally, any OS should do. It should be a flawlessly written middleman layer between flawlessly written hardware and flawlessly written software. But we all know that software is flawed, hardware drivers are flawed, and OS's are flawed. When WinCE comes across a problem in the kernel, it panics and comes crashing down. When Linux comes across a problem in the kernel, it panics and comes down. According to this article, when QNX comes across a problem in the kernel, it cuts off, shuts down, and reboots just the offending section, cutting downtime from 30 seconds to microseconds. That's pretty darned cool.

    Sure, the foundation of your house is just the interface between the ground and your software creation. But if your foundation is bad, no matter how much support the system integrator can provide, your house won't stay up for long. If you're building apartments, that might not matter. If you're building a hospital, your negligence could cost lives.

    And by the way, it's the software that controls the grinding of the lens. If the hardware knew how to grind a lens already, it wouldn't have electronics. The software controls the OS, the OS controls the hardware. Your Software->OS->Hardware diagram should have proven to you how important it is to have a reliable OS in the middle.

    --
    The ______ Agenda
  15. Re:We Will Crush You? by 100lbHand · · Score: 5, Funny

    1. Crush your enemies 2. See them driven before you 3. Hear the lamentations of their women 4. ? 5. Profit!!

    --
    "I'm not high, just stupid" --JY
  16. Wait until... by Bull999999 · · Score: 5, Funny

    I'm pretty sure AOL, RealPlayer, and Bonzi Buddy will find a way to crash QNX.

    --
    1f u c4n r34d th1s u r34lly n33d t0 g37 l41d
  17. Re:OS crashes. by Ivan+the+Terrible · · Score: 4, Insightful

    Er, WinCE doesn't provide "real-time performance", and least not the way the phrase is understood in the embedded world. It has too much latency and not enough determinism. It does, however, provide a familar GUI for embedded devices, so it is only useful in embedded systems where missing a deadline is not catastrophic.

  18. Re:A couple things by cgenman · · Score: 4, Informative

    A device in the wild running WinCE or Linux has had to undergo and pass the same level of testing as a device running another OS to be admitted into medical usage.

    That's why LASIK systems don't run on WinCE.

    --
    The ______ Agenda
  19. ehm? by Horizon_99 · · Score: 5, Informative
    What you won't find in QNX is USB support, drivers for a Sound Blaster 16
    are you sure about that?
  20. Re:A couple things by alienw · · Score: 4, Informative

    Sure, I trust testing. After all, if an OS seems to work right most of the time, it's fine. If my copy of mozilla doesn't crash within an hour, it will never crash. Since the Therac-25 underwent stringent testing, it was perfectly safe, right?

    BZZZZZT! Wrong answer. Evidence shows that testing cannot be trusted to reveal all defects. No matter how much you test a system, there is still a very significant risk that it will contain a defect. That's why practically all critical systems use a PROCESS to prevent errors from getting in. That's why the military forces Ada for all systems, why off-the-shelf components aren't used for life-support systems, and why MIL specs are not just based on reliability tests. Since neither Linux nor WinCE underwent any type of certification, code audit, or specialized quality-control processes, they cannot be trusted despite what tests might indicate.

  21. A fire-and-forget controller... by PSaltyDS · · Score: 5, Interesting

    The US Navy has used a CD-ROM tech library called ATIS for years. It is based on a Kubik 240 CD-ROM changer with an external controller called a Mediator. The mediator runs QNX. I worked on some ATIS systems and found the CD-ROM changer to be an extremely fragile and unreliable electromechanical beast, but NEVER saw a failure, glitch, or error on the QNX based mediator. This was a tribute to the hardware it ran on as much as well as the OS. Interestingly enough, I am intimately familiar with the inside of the Kubik changer, but have no idea what CPU, memory, or disk the Mediator ran on. This was simply because the changer was always broke and the Mediator never had to be touched from the day it was installed.

    People in white lab coats are the primary cause of cancer in rats.

    --
    Any technology distinguishable from magic is insufficiently advanced. - Geek's corollary to Clarke's law
  22. Qnx: Microkernel, real-time, small, and fast by Teckla · · Score: 5, Interesting

    In the mid-80's I frequented a multi-user BBS which ran on Qnx. The machine? A 4.77 MHz 8088 IBM PC clone. It had 10 or 12 lines each running a 300 baud modem. It had email, newsgroups, chat, games, and downloads. I had a developer account and could compile C programs. All while the system was full. Without anyone even noticing. The OS is smooth as silk.

    Later, the BBS was upgraded to an 8 MHz AT clone and 2400 baud modems. Still, smooth as silk, even at capacity.

    The BBS never crashed once and always ran smooth.

    I can't say much about today's Qnx, because I haven't used it. But yesterday's Qnx displayed a level of quality I've never seen in another OS. If I ever find myself needing medical attention, I usre as hell hope the OS running under the hood is Qnx. There is nothing more reliable.

    -Teckla

  23. Re:QNX is still around? by njan · · Score: 5, Informative

    Actually, as far as I remember, they released a bootable iso which had complete hardware support with a huge library of software, and network support - a la knoppix.

    But their floppy was phenomenally useful - on a site of several thousand people, I used to use it in preference to windows to troubleshoot network equipment - until the company stopped to buy floppy drives for their workstations by default...

    --
    I am a viral sig. Please copy me and help me spread. Thank you
  24. Re:QNX? ICK! by dsplat · · Score: 4, Insightful

    I am currently working on a software development project migrating code _away_ from QNX to Linux. Every time I have to work on the old QNX project I want to bang my head against the monitor.

    That can depend a great deal on which version of QNX you are looking at. It you really have an older project that is running on say, QNX 4, then it would be painful. I've worked quite a bit with it. The most painful thing about it is that I remember when Linux looked and felt like that years ago. That's because QNX 6 is current. Most of the things that you've come to expect under Linux are available under QNX.

    Where QNX really shines, is in faster context switches, and a predictable real time scheduler. Of course, if you invert the priority of your processes, good luck. The QNX folks have also provided a nice message passing library. Okay, there are other ways to handle interprocess communication. But their stuff just keeps on working.

    The only reason that I would recommend porting away from QNX to Linux is if there was a specific need driving the port. If all of your other code is under Linux, or you need to save the licensing costs, or there are specific tools or libraries that haven't been ported. QNX has a pretty familiar feel to anyone familiar with multiple Unices.

    Now the GUI libraries (I'm talking QNX 4 here, not the newer Photon stuff), are a bit of a pain. They harken back to darker days. The effort to port QNX 4 GUI code to anything else would be bigger than it is worth in a lot of cases.

    QNX gets the embedded, real time stuff right. Don't underrate that.

    --
    The net will not be what we demand, but what we make it. Build it well.
  25. Re:um by SealBeater · · Score: 5, Informative

    I can't believe this got a +5 insightful.


    It's not made for PCs

    You are mistaken, I'm afraid. See below.


    What you won't find in QNX is USB support

    QNX most defiantly has USB support, as I have a Audrey that has it sitting in front of me.
    As for the "not meant for PCs", QNX runs extremely well on a PC, with just about everything you need.
    QNX also has 3d support, as evidenced in the FAQ here.

    To quote:
    Photon supports rapid animation, 3D graphics, and realtime trending
    through off-screen memory, bypass mode, video overlay, and other
    advanced features.

    QNX also supports the following:

    * XScale processors and boards
    * >4G address spaces on PowerPC boards
    * more video hardware
    * UDMA 66 chipset (high-speed disk interface)
    * Enhanced TCP/IP stack - includes IPv4, Unix domain sockets, multicast support
    * NFS v3
    * Resource database for better device mapping
    * Bi-directional pipes
    * Block driver DMA
    * Enhanced support for shared memory, with full support for creation mode and ownership information

    And SMP, which OpenBSD still hasn't included, for instance.

    I recommend that anyone who is interested download the free ISO and install it on
    a spare computer you may have laying around and see for yourself. Get it here.
    Don't rely on /. or me to give accurate information, go see for yourself.

    SealBeater

    --
    -- Its survival of the fittest...and we got the fucking guns!!!
  26. Re:Some interesting points to note by Kourino · · Score: 4, Insightful

    Well this is somewhat of a generalization. Yes some errors can cause the whole system to crash in both Linux, Windows, and Unix. The difference is that it the way Unix and Linux are designed, it is far less likely.

    What particular Windows design flaw are you thinking of here? (In other words, I'm far from a Microsoft apologist, but it's nice to back up your statements. :3 )

    Protected memory space for the kernel or microkernel: Even Windows has that. The only problem is that "protected" is a very loose term for Windows. Unlike Windows, Unix and Linux doesn't allow any ordinary application to write to the kernel.

    That's funny, I don't seem to remember being able to write to addresses above 0x80000000 on NT4, although I haven't tried loading a pointer with such an address and dereferencing it in purpose. Somebody with immediate access to a Win32 system could try this and tell us what happens:

    #define WIN32_LEAN_AND_MEAN
    #include <windows.h>

    int WINAPI WinMain (HINSTANCE hInstance, HINSTANCE hPrevInstance, LPSTR lpCmdLine, int nCmdShow)
    {
    char *p;
    p = (char *) 0x80000001L; // start of kernel address space + 1
    *p = 0; // this *should* terminate process
    MessageBox (NULL, "Nyah nyah, Kourino doesn't know what he's talking about", "Ha!", 0);
    return 0;
    }
    The expected outcome and possible outcomes should be clear. :D

    (Win32 userland/kernel split is 2:2, unlike Linux's default 3:1. 2:2 seems a bit excessive to me, but ah well; i haven't thought that much about it. I know there are issues in 3:1 for stuff like page tables on large memory machines). If you're thinking of the bad old days of 16-bit Windows, please say so; it's important to know that you're comparing a broken OS implementation.

  27. Re:A couple things by Stephen+Samuel · · Score: 4, Interesting
    1) It isn't the operating system controlling the grinding of lenses or correcting the tilt of the TGV. It is a function of the hardware to do these things. That they report back to some software (which could frankly be run on any embedded OS) which then tells them what to do next is almost irrelevant.

    Only partly true.
    The operating system provides the framework within which the software works. For things like a desktop where things like the occasional 1/2 second ~ 3second delay isn't fatal, and blue-screening a couple of times a week (or day, as the case may be) is mostly just an annoyance, then yes -- the two are pretty much equal.

    For things like nuclear reactor control, precision robotics and medical instruments, where a 1 miliseond (much less 1 second) hickup can result in death and destruction. they are most definitely not equal. The hard realtime in Windows is, well, not that hard. It's pretty easy to get Windows to lock up for the better part of a second. Linus is only slightly better -- but only when you install the realtime patches.

    As far as reliability, Microsoft is still proud of being able to (sometimes) run for 3 months at a shot without rebooting. Linux has a much better history, but it's still far from bulletproof. As far as I know, neither one is certified to run things like nuclear reactors and medical equipment.

    The Navy's decicision to use Windows to run their battleships has been the source of some amusement -- having managed to bluescreen one ship and leaving it 'dead in the water'. As to whether this could happen during a battle, converting 'dead in the water' to 'dead and in the water' is a matter of conjecture. All I can say with certainty is that I'm glad I'm not a US sailor.

    --
    Free Software: Like love, it grows best when given away.
  28. QNX reliability by Space · · Score: 5, Interesting

    I work for a robotics company. We use QNX as the OS on our PC based control. The following is an example of how QNX has impressed me.

    One November a customer called and complained that they were not getting their log files. These log files were written to a ftp shared directory. One of my coworkers logged into the robot via modem and started looking around. When he tried to get a directory listing he got an Input/Output error instead. After a little digging around in the logs in ram he determined the hard drive had died. The most interesting thjing is that the hard drive had apparently died in August. The robot had run continually from August to November and the only trace of any problems was the lack of log files. There was no other permament storage in the system. The OS, UI and all the robot applications were running in RAM for 3 months without problems.
    I Love QNX

    --
    I Don't Work Here
  29. If the Air-Control Syetems ran MS software... by Dr+Reducto · · Score: 5, Funny

    Good thing the FAA uses QNX, cause if they ran MS software, it would go something like this:

    Air Traffic Boss: How's it going?

    Air Traffic Controller: Fine.

    Boss: What's That? (Points to blue screen)

    Controller: Oh, that happens when we try to track more than three planes.

    Boss: Why does it do that?

    Controller: We only purchased a 3-plane license. If we try to track 4, Palladium kicks in, and the whole thing locks up.

    Boss: Doesn't that sound, you know, dangerous?

    Controller: Not as dangerous as this! (plays an illegal mp3, sirens blow, and all machines are shut down, power is cut off, forcing runway lights to turn off, while planes crash like crazy.)

  30. Re:QNX? ICK! by ComputerSlicer23 · · Score: 4, Informative
    Can I call Bullshit on you? As I worked for the first QNX reseller in the United States, I've never worked on QNX 6, but I did a lot of work on QNX 4, and did a bit of porting work from QNX 2 -> QNX 4. I've stayed in touch with some friends there, and they did a lot of the work of writing certain portions of the QNX 4 compatibility layer for QNX 6.

    What security problems did you have?

    There are 2 that I know of offhand. First, they used a reversible hash for passwords, or they used one that was trival to brute force. It's my understanding that breaking a password on QNX is relatively simple. Second, if you are user X on a given machine, you are user X on all of the machines when you are using the QNX networking.

    QNX isn't meant to be an on the public Internet OS. It's meant to be used in a closed loop networking environment when in production use. Don't configure anyone else as on your QNX network, and the problem is solved.

    2. Networking was trivial. The damn network just worked, the biggest trick was coordinating who had what node number. It worked all the time once you got is correctly configured. It always worked. Other then getting the TCP/IP stack installed which took the sacrifice of a small fury animal, and asking my co-worker Bob how to do it. Once it was configured and running, it was trivial, it always worked without fail on the machines I used.

    IPC, was cake. It was stock off the shelf redevous style message passing. About the trickest thing there was calling returning a negative value from a inside of a interrupt service routine (not the real ISR, because you should never reprogram the ISR's, but the function you registered to be called when an interrupt happened), that would call issue a Trigger. That was a little weird. The networking itself was simple. Here's the buffer with the message, here's who I want it passed to, call the send message API. Done.

    Now, the style you had to use was a little awkward, because you blocked on a receive message call. However, that was a function on the hard real time requirement of processing a message. You could use stock TCP/IP functionality if you wanted to. They had the standard UNIX sockets as I recall. The had shared memory (in fact shared memory was how they implemented all of the Dev Server functionality). I can't remember if it did stock UNIX signals (I'm pretty sure it did). However, you never needed to use those, you could send real QNX messages, which was orders of magnitude easier.

    Now, if you want to bitch about the structure of the Photon programs I understand. If you want to bitch about the lack of a number of highly useful utilities, and that all things are freeze/PAX encoded instead of TAR'ed, I'd agree. Networking isn't a problem. IPC is the core of the entire OS, that's literally how it implements everything. Everytime you call open/read/write, a message gets sent to the process that is registered to handle calls to that. I know this because I write a RAM disk buffer as a proof of concept that we could re-implement chunks of the OS if we needed to. Message passing and IPC are what QNX excels at. It's security model is that, don't use it when it's connected to something that isn't trustworthy.

    Kirby

  31. Re:Bullet Proof by Idarubicin · · Score: 5, Funny
    Reminds me of a story from this page:

    About a year ago, I was called out to do field service. When I got to the lady's house and was let in, the first thing I noticed was the smell of gunpowder. The second, the double barreled 12-gauge shotgun lying on the couch. Third, the big gaping hole in the side of her computer. (It was one of those Macs where the CPU and monitor are in the same housing.)

    I looked at her. She was a little grey haired woman, around 60 or so. Had she? Not possible. Still, I had to ask.

    Me: "Did you shoot...?"
    Customer: "Yes, I got a little mad at it. They told me I couldn't hurt it, but I think they were wrong. Can you salvage anything?"

    I mumbled something about not being a Mac tech and told her I would send one out as soon as I could. Then I burned rubber out of there.

    About a month later, my boss called me in; he had the woman on hold. She had apparently complained that I was not competent and that I had lied when I said I would send out a competent Mac tech -- or perhaps I just hadn't been able to find anyone competent working for us. I filled him in. He paused for a second, picked up the phone, and said, "Ma'am? Did you put a shotshell into your computer? ... Uh huh...I'm sorry, ma'am, we really can't...well, no.... I'll try to send one out.... Nice doing business with you...." He hung up, looked at me, and said, "You think any of our Mac techs will go?" I shook my head. "Me neither."

    We heard from her again last week, when my boss told me that the woman had called up to cuss me out, saying not only was I a "young whippersnapper" but also a liar, since one of our competitors had fixed her computer just fine, even fixing the little scratches and stuff on the monitor glass. That sounded fishy, so I went over and talked with the techs. After a case of canned drinks and a few bags of junk food, I wormed the whole story out of them. Apparently, about the only salvagable part was the hard drive (which the buckshot had missed), so they took it out, went out and bought a whole new computer, slapped the hard drive in, and presented it to the lady as her repaired computer -- of course charging her an arm and a leg.

    --
    ~Idarubicin
  32. Message passing is basic by Animats · · Score: 5, Informative
    First, QNX really is a microkernel OS, with networking, drivers, file systems, windowing, etc. running as protected mode processes. MacOS X, Mach, the Hurd, NT, etc. have far, far more in the kernel. Their kernels are an order of magnitude (or worse) bigger.

    The key idea behind QNX is that it does interprocess message passing between protected-mode processes really, really well. Everything else is built on top of that. In most other OSs, interprocess communication was an afterthought, and it shows. Typically, message passing is built on top of the I/O system. In QNX, the I/O system is built on top of message passing.

    The QNX kernel is very stable because it only does a few basic things, and those few things are heavily exercised and well debugged. New system calls are very rarely added. New features go in new user processes.

    Development on QNX is straightforward. The whole GNU command-line toolset is available. The API is Posix-compatible. The QNX calls are well integrated with the Posix calls; there aren't separate "Posix threads", like some other OSs.

    QNX is the last OS vendor that competes commercially with Microsoft on x86 desktop machines. The fact that they're still alive says something.

    You can run QNX as a desktop OS, and I have a machine on my desk that does so. But there's not much desktop-type software. Mozila, AbiWord, and Eclipse have been ported, but that's about it for graphical desktop applications. OpenOffice has not been ported, and it would be a huge win if somebody did that.

    QNX has its own windowing system, Photon, which is like nothing else out there. It's quite good, and much cleaner than most windowing systems. But it's different.

    Hardware support is spotty. Graphics support is mostly for obsolete boards, although anything that supports VGA or VESA modes will work. (NVidia refuses to release enough information to allow development of QNX drivers.) USB 1 is supported, but only for a few peripherals. USB 2 is not, nor is FireWire. (I've been writing FireWire camera support.)

    QNX runs our robot vehicle for the DARPA Grand Challenge. It has to work.

  33. Why not expect QNX-like reliability everywhere? by Knight2K · · Score: 4, Insightful

    I've seen a lot of posts in this thread that make the point that QNX isn't really for workstations/PCs etc... it is for when things absolutely, positively must work always.

    I grant that this is not a requirement for desktop users, for example, because no one's life is usually at stake if your instant message or e-mail doesn't go through (in fact that might be a blessing considering the content of some of them). And it would be really expensive to require all computer programs to be as robust as QNX appears to be.

    But leaving that aside for a second, why shouldn't people expect all computer programs to be that reliable? Why do I have to put up with the annoyance of killing processes or rebooting even if it is just an annoyance? Shouldn't we try to making computing that reliable always? Is it possible?

    I guess it might not be for certain kinds of applications since a user could theoretically input or try to process anything, but it seems that the QNX system isn't written to be bulletproof in that way, it is just written with the assumption to trust nothing and recover gracefully from all errors. Should programs just be that way? Or is it improbable to be able to create a 3-D graphics card/word processor/what-have-you with that kind of reliability?

    Maybe we can't do this because of the anomaly that will become the One or maybe I should have laid off the peyote before writing this, or maybe I would remember something from my CS degree that reveals I am being stupid but can't because I'm too tired. I'm getting ver-clemped: feel free to discuss amongst yourselves or mod me down.

    --
    ======
    In X-Windows the client serves YOU!
  34. Re:Imagine........ by Rolman · · Score: 4, Informative

    I know you were being funny, but actually, a cluster in QNX is the easiest thing to do ever.

    QNX's architecture is very much oriented towards message passing, and every piece of hardware is abstracted, even processors. This means you can have a lot of CPUs or machines working on a network running your applications and the load will be evenly distributed, without you having to specifically code your applications. Your only limit is your network performance and latency.

    Hell, you'd need to code your application with special system calls for it to know it's not running locally!

    I had a wonderful experience with QNX4 a couple of years ago. QNX4 back then didn't have SMP support, but I called QNX Support and they told me how to run one kernel on each CPU of my server and Voila! I had the equivalent of a cluster in one box. Performance was very good, too, context switching was not even worth to measure.

    QNX Neutrino is even more powerful, and now it supports SMP... Beowulf clusters are sooo 1999...

    --
    - Otaku no naka no otaku, otaking da!!!
  35. Re:OS crashes. by IronChef · · Score: 4, Funny

    It does, however, provide a familar GUI for embedded devices...

    I think it is reaching to call WinCE's interface familiar. My first reaction upon using a PocketPC was, "wtf is going on?!"

    I guess it is more familiar than, I dunno, cattle prod torture, but that isn't saying much.

    I love my iPAQ anyway though.

    Zzzzot!

  36. Re:you can download a free copy of Neutrino by Anonymous Coward · · Score: 4, Interesting

    There are a couple of things qnx does that are somewhat quirky, but also unspeakably cool:

    integration of memory, proccess, and file systems. You can address memory as a file. you can refer to processes as file. want a snap shot of your process? just copy it to disk some where.

    linking programs together at run time. Have a constant you want to change, grab it into a simple gui slider with ease. Want to grab images from a frame grabber, just register to recive them. What? they are comming from a frame grabber on another machine? no difference. and this is being routed to a gui running on a third? also not a problem.

    Want to start a bunch of processes on your cluster, link them all via scripts, then move proccesses around to load ballance, relinking as you go? Also not a problem, you can do it with a single script on one machine.

    Having that level of fast comunication primitives is great.

  37. Alternative sources by OzJimbob · · Score: 4, Informative

    If you're still struggling to get it off the offical site, you can find QNX here:

    Planet Mirror.

    A couple of different ISOs are offered - one with all the packages, and a basic ISO. It's able to install within a Windows partition, apparently.

    --
    -"I still believe in revolution; I just don't capitalize it anymore." - srini!
  38. Re:QNX vs. Linux by cait56 · · Score: 4, Informative

    QNX is an embedded OS. As embedded OSs go its very complete. You can get far smaller kernels with fewer pre-packaged solutions, and depending on your application that can be preferable.

    I haven't double-checked things recently, but my recollection was that QNX emphasized distributed systems (especially locally distributed, as in within a factory) more than most kernels. If you're building a distributed message passing system, QNX is great. If you're building a real-time state machine, there are other kernels that might be a better fit.

    Kernels are most applicable for applications where the processor has a very defined purpose and frequently must have very predictable responses. Linux and BSD can be abused to behave that way, but their real strength is their flexibiilty.

    If you need to add new daemons quickly and be confident that you aren't breaking other applications, then you want a "full OS" such as any of the Unixes.

    Personally, I've found the "loaded" kernels (such as VxWorks and QNX) to be of dwindling importance. When I do a system design I tend to end up with environments where I want a full Linux or BSD in order to have the latest in network stacks, or I want complete and total control of the processor. In the latter case I want the smallest kernel that will boot my state machine possible. I don't want efficient thread context switching, in those environments I don't want threads, just objects and state transitions.