|Source model||Closed source|
|Latest release||7.1 / July 2020|
|Marketing target||Embedded systems|
|Package manager||Able to use Pkgsrc framework from NetBSD project|
|Platforms||Current: x86-64, ARM32, ARM64|
Former: MIPS, PowerPC, SH-4, StrongARM, XScale
|Kernel type||RTOS (microkernel)|
QNX (/ˌkjuː ˌɛn ˈɛks/ or /ˈkjuːnɪks/) is a commercial Unix-like real-time operating system, aimed primarily at the embedded systems market. QNX was one of the first commercially successful microkernel operating systems. As of 2020[update], it is used in a variety of devices including cars and mobile phones.
The product was originally developed in the early 1980s by Canadian company Quantum Software Systems, later renamed QNX Software Systems. The company was ultimately acquired by BlackBerry Limited in 2010.
As a microkernel-based OS, QNX is based on the idea of running most of the operating system kernel in the form of a number of small tasks, named Resource Managers. This differs from the more traditional monolithic kernel, in which the operating system kernel is one very large program composed of a huge number of parts, with special abilities. In the case of QNX, the use of a microkernel allows users (developers) to turn off any functions they do not need without having to change the OS. Instead, such services will simply not run.
To demonstrate the OS's capability and relatively small size, in the late 1990s QNX released a demo image that included the POSIX-compliant QNX 4 OS, a full graphical user interface, graphical text editor, TCP/IP networking, web browser and web server that all fit on a bootable 1.44 MB floppy disk for the 386 PC.
QNX Neutrino (2001) has been ported to a number of platforms and now runs on practically any modern central processing unit (CPU) family that is used in the embedded market. This includes the PowerPC, x86, MIPS, SH-4, and the closely interrelated of ARM, StrongARM, and XScale.
QNX offers a license for noncommercial and academic users.
The BlackBerry PlayBook tablet computer designed by BlackBerry uses a version of QNX as the primary operating system. Devices from BlackBerry running the BlackBerry 10 operating system are also based on QNX.
QNX is also used in car infotainment systems with many major car makers offering variants that include an embedded QNX architecture. It is supported by popular SSL/TLS libraries such as wolfSSL.
In recent years QNX has been used in automated drive or ADAS systems for automotive projects that require a functional safety certification. QNX provides this with its QNX OS for Safety product.
The QNX operating system also contained a web browser known as 'Voyager'.
Gordon Bell and Dan Dodge, both students at the University of Waterloo in 1980, took a course (CS452) in real-time operating systems, in which the students constructed a basic real-time microkernel and user programs. Both were convinced there was a commercial need for such a system, and moved to the high-tech planned community Kanata, Ontario, to start Quantum Software Systems that year. In 1982, the first version of QUNIX was released for the Intel 8088 CPU. In 1984, Quantum Software Systems renamed QUNIX to QNX in an effort to avoid any trademark infringement challenges.
One of the first widespread uses of the QNX real-time OS (RTOS) was in the nonembedded world when it was selected as the operating system for the Ontario education system's own computer design, the Unisys ICON. Over the years QNX was used mostly for larger projects, as its 44k kernel was too large to fit inside the one-chip computers of the era. The system garnered a reputation for reliability and became used in running machinery in many industrial applications.
In the late-1980s, Quantum realized that the market was rapidly moving towards the Portable Operating System Interface (POSIX) model and decided to rewrite the kernel to be much more compatible at a low level. The result was QNX 4. During this time Patrick Hayden, while working as an intern, along with Robin Burgener (a full-time employee at the time), developed a new windowing system. This patented concept was developed into the embeddable graphical user interface (GUI) named the QNX Photon microGUI. QNX also provided a version of the X Window System.
Toward the end of the 1990s, the company (now called QNX Software Systems) began work on a new version of QNX, designed from the ground up to be symmetric multiprocessing (SMP) capable, and to support all current POSIX application programming interfaces (APIs) and any new POSIX APIs that could be anticipated while still retaining the microkernel architecture. This resulted in QNX Neutrino, released in 2001.
Along with the Neutrino kernel, QNX Software Systems became a founding member of the Eclipse consortium. The company released a suite of Eclipse plug-ins packaged with the Eclipse workbench in 2002, and named QNX Momentics Tool Suite.
In 2004, the company announced it had been sold to Harman International Industries. Before this acquisition, QNX software was already widely used in the automotive industry for telematics systems. Since the purchase by Harman, QNX software has been designed into over 200 different automobile makes and models, in telematics systems and in infotainment and navigation units. The QNX CAR Application Platform was running in over 20 million vehicles as of mid-2011. The company has since released several middleware products including the QNX Aviage Multimedia Suite, the QNX Aviage Acoustic Processing Suite and the QNX HMI Suite.
The microkernels of Cisco Systems' IOS-XR (ultra high availability IOS, introduced 2004) and IOS Software Modularity (introduced 2006) are based upon QNX.
In September 2007, QNX Software Systems announced the availability of some of its source code.
On April 9, 2010, Research In Motion announced they would acquire QNX Software Systems from Harman International Industries. On the same day, QNX source code access was restricted from the public and hobbyists.
In September 2010, the company announced a tablet computer, the BlackBerry PlayBook, and a new operating system BlackBerry Tablet OS based on QNX to run on the tablet.
On October 18, 2011, Research In Motion announced "BBX", which was later renamed to BlackBerry 10, in December 2011. Blackberry 10 devices build upon the BlackBerry PlayBook QNX based operating system for touch devices, but adapt the user interface for smartphones using the Qt based Cascades Native User-Interface framework.
At the Geneva Motor Show, Apple demonstrated CarPlay which provides an iOS-like user interface to head units in compatible vehicles. Once configured by the automaker, QNX can be programmed to hand off its display and some functions to an Apple CarPlay device.
On December 11, 2014, Ford Motor Company stated the company would be replacing Microsoft Auto with QNX.
In January 2017, QNX announced the upcoming release of its SDP 7.0, with support for Intel and ARM 32- and 64-bit platforms, and support for C++14; it was released in March 2017.
The QNX kernel,
procnto, contains only CPU scheduling, interprocess communication, interrupt redirection and timers. Everything else runs as a user process, including a special process known as
proc which performs process creation and memory management by operating in conjunction with the microkernel. This is made possible by two key mechanisms: subroutine-call type interprocess communication, and a boot loader which can load an image containing the kernel and any desired set of user programs and shared libraries. There are no device drivers in the kernel. The network stack is based on NetBSD code. Along with its support for its own, native, device drivers, QNX supports its legacy, io-net manager server, and the network drivers ported from NetBSD.
QNX interprocess communication consists of sending a message from one process to another and waiting for a reply. This is a single operation, called
MsgSend. The message is copied, by the kernel, from the address space of the sending process to that of the receiving process. If the receiving process is waiting for the message, control of the CPU is transferred at the same time, without a pass through the CPU scheduler. Thus, sending a message to another process and waiting for a reply does not result in "losing one's turn" for the CPU. This tight integration between message passing and CPU scheduling is one of the key mechanisms that makes QNX message passing broadly usable. Most Unix and Linux interprocess communication mechanisms lack this tight integration, although a user space implementation of QNX-type messaging for Linux does exist. Mishandling of this subtle issue is a primary reason for the disappointing performance of some other microkernel systems such as early versions of Mach. The recipient process need not be on the same physical machine.
All I/O operations, file system operations, and network operations were meant to work through this mechanism, and the data transferred was copied during message passing. Later versions of QNX reduce the number of separate processes and integrate the network stack and other function blocks into single applications for performance reasons.
Message handling is prioritized by thread priority. Since I/O requests are performed using message passing, high priority threads receive I/O service before low priority threads, an essential feature in a hard real-time system.
The boot loader is the other key component of the minimal microkernel system. Because user programs can be built into the boot image, the set of device drivers and support libraries needed for startup need not be, and are not, in the kernel. Even such functions as program loading are not in the kernel, but instead are in shared user-space libraries loaded as part of the boot image. It is possible to put an entire boot image into ROM, which is used for diskless embedded systems.
Neutrino supports symmetric multiprocessing and processor affinity, called bound multiprocessing (BMP) in QNX terminology. BMP is used to improve cache hitting and to ease the migration of non-SMP safe applications to multi-processor computers.
Neutrino supports strict priority-preemptive scheduling and adaptive partition scheduling (APS). APS guarantees minimum CPU percentages to selected groups of threads, even though others may have higher priority. The adaptive partition scheduler is still strictly priority-preemptive when the system is underloaded. It can also be configured to run a selected set of critical threads strictly real time, even when the system is overloaded.
QNX RTOS History
|Beta||1983||As QNX Beta|
|2.0||1987||Elements of 4.3BSD like TCP/IP and PPP merged into QNX 2.0.|
|4.1||1994||Elements of 4.4BSD into QNX 4.1|
|4.24||1995||QNX/Neutrino 1.0 is forked from QNX 4.24|
|4.25||1997||QNX 4.25 continues after fork with QNX/Neutrino 1.0.|
QNX/Neutrino Microkernel history—Forked from QNX 4.24 in 1996.
|1.0||1996||QNX/Neutrino 1.0 as forked from QNX 4.24|
|2.10||1999||QNX/Neutrino 2.10 (QRTP)|
|6||January 18, 2001||QNX RTOS 6|
|6.1.0||2001||QNX RTOS 6|
|6.1.0 (patch A)||September 28, 2001|
|6.2||June 4, 2002||QNX 6.2 (Momentics)|
|6.2 (patch A)||October 18, 2002||QNX 6.2|
|6.2.1||February 18, 2003||QNX 6.2.1 (Momentics)|
|6.3||June 3, 2004||QNX 6.3|
|6.4.0||October 30, 2008||QNX Neutrino RTOS 6.4.0|
|6.4.1||May 2009||QNX Neutrino RTOS 6.4.1|
|6.5.0||July 2010||QNX Neutrino RTOS 6.5.0 is forked to produce BBX,|
as announced on October 18, 2011, and later previewed,
named "BlackBerry 10 OS" on May 1, 2012.
|6.5 SP1||July 11, 2012||QNX Neutrino RTOS 6.5 SP1|
|6.6||February 28, 2014||QNX 6.6|
|7.0||January 4, 2017||QNX SDP 7.0, first version with 64-bit support|
|7.1||July 23, 2020||QNX SDP 7.1|
Due to its microkernel architecture QNX is also a distributed operating system. Dan Dodge and Peter van der Veen hold U.S. Patent 6,697,876: Distributed kernel operating system based on the QNX operating system's distributed processing features known commercially as Transparent Distributed Processing. This allows the QNX kernels on separate devices to access each other's system services using effectively the same communication mechanism as is used to access local services.
OpenQNX is a QNX Community Portal established and run independently. An IRC channel and Newsgroups access via web is available. Diverse industries are represented by the developers on the site.
Foundry27 is a web-based QNX community established by the company. It serves as a hub to QNX Neutrino development where developers can register, choose the license, and get the source code and related toolkit of the RTOS.
Edited: 2021-06-18 18:50:04