Real-time operating systems, designed to work using real-time inputs and special scheduling algorithms, are frequently employed in embedded applications. In general, what makes an RTOS "real-time" is its support for multitasking, process threads that can be prioritized, and a sufficient number of interrupt levels. Another aspect of RTOS is that the computation it provides cannot only be "correct" (as in traditional operating systems), but that it has to be correct within a certain time constraint.
This article provides a quick glance at seven RTOS manufacturers to give you an idea of what's available that is certified to work on Power Architecture™ processors.
And since alphabetical-order listing is fair (but not for the guy at the end of the alphabet), this time we're going in reverse order:
- Wind River Systems
- QNX Software Systems Ltd.
- MontaVista Software Inc.
- LynuxWorks Inc.
- Green Hills Software Inc.
- Enea Embedded Technology AB
- DENX Software Engineering
At the 2005 Embedded Systems Conference in San Francisco, Wind River CEO Ken Klein delivered five survival strategies for embedded systems engineers (to keep from becoming "roadkill"):
- Stop trying to do it all yourself.
- Share. There is power in numbers, in standardization, in collaboration.
- Do not take change personally. Roll with the decisions.
- The people in the boardroom have one view and you have another. When you see a potential problem (or solution), send it up the chain of command.
- "Be flexible. Be plugged in. Be up to date. Be ready to jump to the next new thing." According to Ken, "If you tie your professional identity and your professional worth to a particular technology, I can guarantee you that the next bus in the carpool lane is going to run you down. Splat. End of story."
This kind of thinking is behind the Wind River strategy in device software optimization, offering operating systems, development tools, middleware, and services for a variety of industries.
Wind River products include:
- The General Purpose Platform, Linux™ Edition and Platform for Network Equipment, Linux Edition: For those requiring Linux runtime capabilities, both distributions contain a high-performance, pre-emptible kernel.
- VxWorks Platforms, based on VxWorks 6, are offered with the following target-related focuses: automotive devices, consumer devices, industrial devices, and network equipment.
Wind River is also presenting as a part of the IBM WebSeries on the PowerPC 970.
So, is the Space Shuttle arm the only piece of Canadian technology aboard the Discovery? The answer is no -- the laser camera at the end of the arm, used to examine the exterior of the shuttle is from Canadian manufacturer Neptec. And the RTOS that runs the camera is the QNX Neutrino.
For more than 25 years, QNX Software Systems has provided OS technology, development tools, and professional services to build mission-critical embedded systems. The ancestor of QNX Neutrino started in 1980 as a microkernel architecture that provided modularity, fault tolerance, and dynamic scalability. Early QNX OS technology focused on x86 platforms (QNX produced the first OS to support a hard disk, to offer protected-mode computing, and the first RTOS to run on a 386).
QNX products include:
- QNX Neutrino RTOS, a "true" microkernel operating system under which every driver, application, protocol stack, and file system runs outside the kernel, in the safety of memory-protected user space.
- QNX Momentics Development Suite for building and optimizing applications for QNX Neutrino.
- Board Support Packages for QNX Momentics (including a huge range of PPC BSPs).
In October 2004, MontaVista launched the Open Source Real-Time Linux Project with a goal of further reducing interrupt latency and reducing task-preemption latency in the 2.6 kernel (also to achieve preemption latency bounded by the worst case IRQ disable). To do this, the company contributed reference implementations based on its work in the area of real-time Linux determinism. Community input has taken that original reference concept and made it into a full-fledged real-time kernel that is suitable to run high-end multimedia and other time-critical embedded applications for the mobile handset and telecommunications markets.
MontaVista has added to that effort by releasing (in August 2005) native, hard real-time developments to the Linux kernel that filter the roughly six million lines of Linux code down to around 100 critical interrupt-code segments.
MontaVista Software products include:
- MontaVista Linux for Embedded Devices provides a common source and binary platform across a broad range of processor architectures.
- MontaVista Linux for Communications Infrastructure provides functionality specifically for Telecom and Datacom with high availability, hardening, and real-time performance.
- MontaVista Linux for Consumer Electronics, an embedded Linux product targeted at advanced consumer electronics devices.
- MontaVista Linux for Mobile Devices (Mobilinux), an optimized Linux operating system and development environment, ideally suited for wireless handsets and mobile devices with requirements for power management, hard real-time performance, fast start-up, and small footprint.
MontaVista is also presenting a broadcast on the PowerPC 970 for the IBM WebSeries.
Established in 1988, LynuxWorks provides operating systems, software-development products, and consulting services for the embedded software market for such industries as communications, aerospace/defense, and consumer products. The company is a founding member of the Embedded Linux Consortium.
All three LynuxWorks's OS have priority preemption capability to address event-driven activities. BlueCat is a standard Linux distribution with the open software scheduling algorithms which include some preemption points for priority management. LynxOS is a hard RTOS with priority response at the micro-second level. LynxOS 178 has a time- and space-defined environment in which each partition is guaranteed a time-shared slot in a round robin manner, overriding the priority preemption capability.
LynuxWorks products include:
- BlueCat embedded Linux is based on the 2.6 kernel and enhanced for use in embedded systems ranging from small consumer-type devices to large-scale, multi-CPU systems.
- LynxOS 4.0 is a hard RTOS for original equipment manufacturers and telecommunications equipment manufacturers to help them construct sophisticated real-time systems.
- LynxOS-178 is derived from LynxOS and is a virtual machine(VM) operating system enhanced for use in military, business/regional aviation and air transport; it removes the need for multiple systems in a certified environment through a partitioning kernel that allows for many virtual machines to run on a single piece of hardware, with each VM having no knowledge of other VMs.
Green Hills Software, Inc. produces high performance compilers, software development tools, and real-time operating systems (RTOS) for developers of embedded systems.
Dan O'Dowd, Green Hills founder, commented on the origins of the company:
When we started, we were a compiler company, supplying compilers to the OS suppliers. Then, the introduction of Windows® was a key event for us. We thought Windows would change the landscape for how a multiwindow debugger would work, with more information and a new style of graphical programming. In 1996, we thought the RTOS business looked pretty good. The RTOS companies decided they could do their own debuggers and tools, and we decided we could do our own RTOS.
Green Hills products include:
- The velOSity is a small, fast, royalty-free microkernel designed for high-volume and resource-constrained embedded applications; it comes with embedded software tools, kernel services, device drivers, BSPs, and middleware.
- INTEGRITY is a secure, royalty-free RTOS (built on the velOSity kernel) for use in embedded systems.
Green Hills is also presenting as a part of the IBM WebSeries on the PowerPC 970.
Enea's business revolves around its OSE real-time operating system coupled with consulting services and third-party software. Originally specializing in telecommunications (radio base stations and mobile telephones), the company has also found success in the automotive and medical technology industries.
According to Enea, when it comes to a definition for "real time,"
A system is considered real-time capable (according to DIN 44300) when it can respond to an exterior event under all conditions with a defined (deterministic) response ... it is crucial that the response occurs within a predetermined time frame. If this period is exceeded, the system's overall behavior is no longer predictable and the system is not considered to be real-time capable.
And the difference between hard and soft real time:
This category of "hard real time" is frequently weakened somewhat for non-critical systems (or, systems that cannot cause life-threatening harm or material damage). With "soft" real time, exceeding the time interval is tolerated.
Enea's products include:
- The OSE RTOS offers three kernels: OSE, a feature-rich RTOS for complex infrastructure systems and fault-tolerant safety-critical projects; OSE Epsilon, a low-cost, small-footprint, very fast RTOS for deeply embedded and SoC development; OSEck, a "compact kernel" for DSPs.
- Polyhedra is a lightweight, high-performance, in-memory database.
DENX Software Engineering provides embedded and RTOS software engineering services with a strong focus on open source software like Linux, FreeBSD, NetBSD, and more. The company offers firmware and OS porting; authoring of low-level, hardware-related, or device driver software components; development, customization, optimization, and installation of embedded systems software; tools for automatic software updates; and security.
When Wolfgang Denk, founder and CEO of DENX Software Engineering, was asked about his company's business model, he answered, "Looking at the big Linux vendors like RedHat, SuSE, MandrakeSoft, etc., it seems really difficult to make profit by selling Free Software as a product." He added that DENX got a clue from those vendors: "In short: we sell our time and experience."
When asked about the challenges embedded Linux OS, tools, and services vendors face, Denk singled out fragmentation and pointed to the abundance of Linux kernel source trees there are for PowerPC systems.
DENX products include:
- RTAI Real-Time Extension for PowerPC Linux patches for PowerPC processors.
- U-Boot: Open Source Firmware for Embedded PowerPC (ported to more than 275 boards).
- Embedded Linux Development Kit (that supports a wide range of PowerPC target processors such as 8xx, 82xx, 7xx, 74xx, and and 4xx - all components are free; also available for ARM and MIPS processors).
- And various other Linux- and PPC-related products.
If you'd like us to profile your Power-related product, please let us know at dwpower@us.ibm.com.
|
- Companies profiled
- PartnerWorld
has a new look and organization! Learn more about partnering with IBM to
leverage your company's products and technologies.
- Three of the partners profiled today, Wind River, MontaVista, and Green
Hills, are presenting
IBM WebSeries
webcasts this month.
-
Interested in realtime and real-time Linux? You'll want to check out the
Directions interview with IBM Distinguished Engineer Paul
McKenney in the current edition of the newsletter.
-
Return to the front page of the Power
Architecture Community Newsletter 15 August 2005, or view the current issue
of the Power Architecture Community Newsletter.
The developerWorks Power Architecture editors welcome your comments on this article. E-mail them at dwpower@us.ibm.com.
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