Qnx Software Interrupts
Download microsoft powerpoint 2003. QNX Software Systems jpschaffer@. Usecs Pre-emptable A Kernel call is a software interrupt Process Manager Thread Sync. QNX Corporate Sales Presentation Author.
Introduction By: Thomas W. Burger In the late 1990’s, the Web appliance was touted as the next “big thing”, a new device for an emerging market that would create a next generation of consumer IT giants. At the Consumer Electronics Show in Las Vegas, Nevada and the QNX 2000 International Technology Conference in Vancouver, British Columbia many vendors, large and small, showed off multiple visions of the future. Intel built a Web appliance based on Linux.
Microsoft partners made Web Companions based on a scaled down version of the Windows. CE operating system.
Many others, like 3Com’s prototype and the Netpliance iOpener., were based on QNX. At that time Web appliances seemed the likely next step in consumer electronics. Simpler than PCs, they also offered far less functionality. At best they could be considered, as Ken Kalinoski, VP of development at Netpliance called it, a “Rich Client” device that required a dedicated and proprietary server to connect to. The subsequent lack of Web appliances on the shelves of Best Buy and Walmart showed that consumers did not want an appliance that could browse the Web and perform simple email tasks but could not do even simple word processing or store data.
Web devices were being sold at less than cost in anticipation of service revenues that never came. Consumers also did not like the idea of being tied to a specific service provider. Linux and QNX gained notoriety because of the obvious potential for both as the operating systems and development platforms for Web appliances. Linux had mostly been used as a server OS and QNX mainly as an industrial embedded Real Time Operating System (RTOS).To exploit this new market, many developers discovered the capabilities of Linux and QNX in developing smaller, more capable portable devices.
In hindsight, the Web appliance was an idea ahead of technology. There was the software and engineering talent available to produce these devices, but not the hardware and infrastructure to allow the functionality, versatility, and portability required to make the Web appliance the new must-have tech-toy. Advances in cell phone and PDA technology, improvements to digital cameras, lower power requirements, and greater memory capacities, far greater embedded/mobile CPU speeds, and, possibly the most important factor, 802.11b and 802.11g WiFi wireless networking has the Web appliance resurrected as a multifunction device. This combines a computer, organizer, office software suite, cell phone, camera (still and movie), pager, music player, and, of course, email system and Web browser into a single wireless unit that fits in a pocket. Four years later, an eternity in technology terms, we are on the verge of a new “Next Big Thing”. Advances in hardware and in-place wireless and service infrastructure for the already enormous PDA and Internet capable cellphone market has created a great demand for devices that can do more, are more compact and have longer battery life. This has renewed interest in embedded development platforms that can provide the requirements necessary to compete in a market that is worth billions of dollars.
This is where the design similarities end. Linus Torvalds designed Linux to run on a standard PC hardware as a generalized OS using a monolithic kernel archi tecture. The kernel contains almost all of the functionality of the entire OS. In contrast QNX was designed to be extremely modular and scalable. QNX is a realtime operating system based on a microkernel - small enough to be embedded on a chip but capable of running a workstation or a large networked server system. Linux for Embedded Development Designers of embedded systems have long used the Linux operating system, because of its robustness, relative compactness, versatility, low cost, and open source licensing model.
Linux lets the designer leverage a large pool of developers, a rich legacy of source code, and industry-standard Portable Operating System Interface (POSIX) APIs. The standard Linux kernel does not have realtime capabilities (predictable response times and microsecond latencies, often referred to as deterministic behavior) that many embedded systems demand such as fly-by-wire controls, ABS braking systems, continuous media, and medical devices. But, Linux can be used as is in consumer devices that are not subject to deterministic issues. In order to provide for the requirements of embedded devices now being developed, where more predictable speed and timing behaviors are required, several Linux products have emerged.
Using Linux in an Embedded System Although Linux was designed to run PC platforms, Linux can be a reliable OS for embedded systems. The typical shrink-wrapped Linux system has a full featured Linux kernel that requires about 1 MB of memory. The Linux “pure” kernel (virtual memory and all core operating system functions) actually consumes only about 100K.
Qnx Software Interrupts
With the networking stack and basic utilities, a complete Linux system runs in about 500K of memory. The total memory required is dictated by the applications to be run, but a Linux system can be adapted to work with as little as 256 KB ROM and 512 KB RAM. So it's a lightweight operating system to bring to the embedded market.
Another benefit of using an open source Linux over a traditional RTOS is that the Linux development community tends to support new protocols faster and more device drivers than RTOS vendors do. The core Linux operating system itself has a fairly simple microkernel architecture. Networking and file systems are layered on top of the microkernel in a modular fashion. Drivers and other features can either be compiled in or added to the kernel at run-time as loadable modules. This provides a highly modular building-block approach to constructing a customized embedded system, which typically uses a combination of custom drivers and application programs to provide the added functionality. An embedded system also often requires generic capabilities, which, in order to avoid re-inventing the wheel, are built with off-the-shelf programs and drivers, many of which are available for common peripherals and applications. Linux can run on most microprocessors with a wide range of peripherals and has a ready inventory of off-the-shelf applications.
Linux is also well-suited for embedded Internet devices, because of its support of multiprocessor systems, which lends it scalability. This capability gives a designer the option of running a r ealtime application on a dual processor system, increasing the total processing power. So you can run a Linux system on one processor while running a GUI, for example, simultaneously on another processor.
A disadvantage to running Linux on an embedded system is that the Linux architecture can not provide realtime performance in its standard form. For instance, standard Linux has tasks scheduled according to a fairness algorithm that gives an equal share of processor time to each task. The solution is to modify Linux to behave in a deterministic manner through the addition of realtime changes in one of following methods:. The first solution is to add software modules that run in the kernel space, the portion of the operating system that implements the scheduling policy, hardware-interrupts exceptions and program execution. Since these realtime software modules run in the kernel space, a code error can impact the entire system's reliability by crashing the operating system.
The second solution, illustrated in Figure 1.,is the dual-kernel approach that provides a runtime environment for realtime tasks. This approach requires developers to write new drivers and system services although equivalent services already exist in the standard Linux kernel. This RTOS solution can slow load time and the increase size of the OS footprint. Figure 1 - Linux with Dual Standard and RTOS Kernel. The third solution is that other embedded Linux vendors use a kernel rewritten to provide RTOS functionality by rewriting portions of the code, such as the scheduler, to be deterministic in behavior. Standardization of Embedded Linux There are over 200 distributions of Linux and many embedded versions. Without the existence of a standard for embedded Linux, so that a single unified platform specification can enable the use of a cost-effective, focused environment, Linux could be all but useless.
In order to make embedded Linux versions compatible the Embedded Linux Consortium (ELC) was formed. ELC is a nonprofit, trade association for the advancement, promotion and standardization of Linux throughout the embedded computing market.
Members participate in management, promotion, implementation, and platform specification working groups in order to enjoy the benefits that standardization brings. The ELC mission statement is “.to make Linux a top operating system choice for developers designing embedded systems.” Dr. Inder Singh, ELC Chairman and CEO of LynuxWorks commented “Linux is rapidly becoming the leading choice for the operating system for consumer electronic products, which are being designed with more and more embedded software.' Karen Chupka, vice president of events and conferences for the Consumer Electronics Association states, “Operating system software is a critical consideration for a rapidly growing list of consumer electronic products.
Linux is destined for growth in 2004” More than 75 companies have now joined the Consumer Electronics Linux Forum (CELF), formed by Sony and Matsushita, to promote Linux-based digital CE products. Some of the other CE companies involved in the forum, officially launched in June of 2003, are NEC, Hitachi, Royal Philips, Samsung, Sharp and Toshiba.
Three Embedded Linux Versions MontaVista Consumer Electronics Edition 3.0 MontaVista has introduced a version of its embedded Linux platform for consumer electronics devices. MontaVista “Consumer Electronics Edition 3.0”. (CEE.) is an embedded OS.
It is aimed at applications such as mobile phones, digital TVs, set-top boxes, and automotive telematics. CEE is designed for highly constrained mobile devices that require low power consumption, restricted memory size and short boot and resume times. It is claimed to be the first commercial, embedded Linux distribution specifically designed for the consumer electronics market, CEE supports dynamic power management features, file system enhancements, and tools to measure performance, system timing, memory size, and supports streaming media optimizations. You might also want to look at the SRRIPC Linux kernel module. It is an almost-perfect implementation of the QNX-4 send/receive/reply API, including message passing, proxies, timers and signals that trigger proxies, and user-space interrupt handling.
It slightly extends QNX-4 behaviour to allow each thread in a process to have its own SRR communication (QNX-4 has no threads, so there's no analog in QNX). Unlike SIMPL, the goal was to provide source-compatibility between QNX-4 and Linux. Also, unlike SIMPL, it does not implement QNX-4 networking. SRRIPC is available as a download at It's a commercial site, but the SRRIPC module is GPL. UPDATE March 2012 Linux for Embedded Development Although still true for mainstream kernels the The PREEMPTRT patch set incorporates preemptive and deterministic features and is available with several Linux distributions or by building an upstream kernel manually. The PREEEMPTRT patchset includes: Preemptible spinlocks (in-kernel locking sections) through reimplementation with rtmutexes. Portions of the kernel that are not safe for preemption are converted to raw spinlocks.
Preemptible critical sections. Priority inheritance for spinlocks and semaphores. Interrupt handlers (soft) converted to preemptible kernel threads. SEE: http://publib.boulder.ibm.com/infocenter/lnxinfo/v3r0m0/index.jsp?topic=%2Fperformance%2Frtbestp%2Fpreempt.htm.
@Luiz Costa - Sorry for the delay in getting back to you. It looks like QNX was developing dual compatibility with Linux but this was dropped when RIM bought QNX to build the PlayBook OS.
However now that RIM is trying to save the PlayBook tablet by providing a compatibility layer that can run Android (which in basically a custom Linux) the idea of dual OS (QNX + Linux) seems to have been implemented. We'll see how this works when PlayBook OS 2.0 comes out - hopefully on time - February 17, 2012 is the rumor. You should alos refer to material available regarding Linux installations that run a standard Linux kernel and an RTOS version to handle real time functions. I bought a PlayBook to try it out and compare it to my three other tablets (Lenovo K1, ViewPad 7, and Kindle Fire) and it was a mixture of love and hate. The PlayBook is superior in form and function and the built in software is generally good with a few nagging little and not so little problems (that really should have already been addressed prior to launch). Playing movies is like running them on my $1200 Win7 laptop.
The picture is great and the sound is good on the speakers (a little tinny) and great on my headphones. I'm going to get a mini-HDMI cable and try it as a DVR for my TV. Other elements like the browser are also decent. However, there are glaring omissions like lack of a mail client (to be addressed in version 2.0 according to RIM). The biggest thing is a lack of available apps. IPad and Android users are spoiled rotten at the plethora of cheap and free and remarkably good apps available.
The PlayBook store is comparably a desert and a couple of the free apps I tried did not even come close to working at all which makes me leery of paying for apps I would like to buy. Getting to the point, the PlayBook OS 2.0 due out mid February 2012 (the 17th is reported but unconfirmed) adds the ability for developers to put a wrapper around Android apps and make them QNX playable. Hacks using rooting are reported (I have not tried them but the rudely named DingleBerry seems to work) that allows a user to install a 'PlayBooked' (placed in a compatibility wrapper) Android launcher and run Android apps without modification. If you can't beat them join them. @Luiz Costa - Sorry for the delay in getting back to you. It looks like QNX was developing dual compatibility with Linux but this was dropped when RIM bought QNX to build the PlayBook OS. However now that RIM is trying to save the PlayBook tablet by providing a compatibility layer that can run Android (which in basically a custom Linux) the idea of dual OS (QNX + Linux) seems to have been implemented.
We'll see how this works when PlayBook OS 2.0 comes out - hopefully on time - February 17, 2012 is the rumor. I bought a PlayBook to try it out and compare it to my three other tablets (Lenovo K1, ViewPad 7, and Kindle Fire) and it was a mixture of love and hate. The PlayBook is superior in form and function and the built in software is generally good with a few nagging little and not so little problems (that really should have already been addressed prior to launch). Playing movies is like running them on my $1200 Win7 laptop. The picture is great and the sound is good on the speakers (a little tinny) and great on my headphones.
I'm going to get a mini-HDMI cable and try it as a DVR for my TV. Other elements like the browser are also decent.
However, there are glaring omissions like lack of a mail client (to be addressed in version 2.0 according to RIM). The biggest thing is a lack of available apps. IPad and Android users are spoiled rotten at the plethora of cheap and free and remarkably good apps available. The PlayBook store is comparably a desert and a couple of the free apps I tried did not even come close to working at all which makes me leery of paying for apps I would like to buy. Getting to the point, the PlayBook OS 2.0 due out mid February 2012 (the 17th is reported but unconfirmed) adds the ability for developers to put a wrapper around Android apps and make them QNX playable.
Hacks using rooting are reported (I have not tried them but the rudely named DingleBerry seems to work) that allows a user to install a 'PlayBooked' (placed in a compatibility wrapper) Android launcher and run Android apps without modification. If you can't beat them join them. Currently I'm assigned to write an article explaining moving development from QNX to Linux. I guess some QNX developers either want to expand to Linux or perhaps are nervous over RIM's troubles and don't want to be stuck if QNX gets orphaned. Tom, I'm a professor at Ferris State University in Michigan and, after reading your article 'Embedded Development - QNX. or Linux.? I wonder if this idea of dual OS (QNX + Linux) has been implemented.
The other question I have is if there is any library available to send emails from a QNX process/thread. This term I started teaching a RTOS course to senior students and am in the process of re-engineering the lab activities around QNX Neutrino. The labs are designed around the idea of implementing the OS concepts presented in class to design tools to control academic robotic arms.
Any ideas or materials that you might have to help us develop this lab, are deeply appreciated. Sincerely, Luiz Costa.