Microsoft Windows still appears to be ruling the roost in South Africa when it comes to the installation of new automation and control systems, although there is evidence to suggest that it is losing market share elsewhere in the world.
The preferred use of Windows is despite its record of instability associated with many previous releases and one must ask if engineers really look for an alternative. With its massive share of the PC market (apart from a few dedicated Macintosh users) we have all become too familiar with the Windows operating environment. Despite the other alternatives (including those for PCs) the easy choice is to stay with something with which you are familiar even though other operating systems may offer a better solution, are just as user-friendly as Windows, and offer greater system stability.
The Linux operating system (OS) has not received much previous coverage in SA Instrumentation & Control and it is thus worthwhile to trace its origins and features. Basically it is a UNIX-like operating system initially developed as a hobby by a student named Linus Torvalds at a Finnish University. In 1994 Version 1.0 of the Linux kernel was released under the General Public License, and the source code is freely available. This kernel is the core of the Linux OS, and literally hundreds of companies, organisations and individuals have released their own versions of operating systems based on this. Torvalds is still working full-time on the kernel and the latest full-featured Version 2.6 was released during December 2003.
Officially Linux is not after the Microsoft PC market but is instead chasing UNIX out of the enterprise server scene. IBM, Hewlett-Packard and other giants in the computing world have embraced Linux and support its ongoing development. More than a decade after its release Linux has been adopted primarily as a server platform.
Although not specifically targeting the desktop market, Linux is seeing increasing home and office usage. A unique feature is that the OS need not even be loaded onto the hard drive, but will run from a CD on any computer capable of booting from a CD drive (see for example, www.knoppix.org) You can even run Linux and Windows on the same PC although Windows should probably be loaded first as otherwise it may destroy information left by the bootloaders. As a result of Microsoft's monopoly, most computers acquired today already have windows loaded and Linux users are recommended that the hard disk (C:) be divided into two separate partitions so that Linux and Windows can operate totally independently (see www.vmware.com for running multiple operating systems simultaneously on a single PC). Home and office Linux users claim higher reliability, less software bugs, freedom from virus attacks (these guys are targeting Windows) and a full suite of user friendly word processor, financial, spreadsheet and e-mail tools that equal the best from Microsoft or Corel, most of these being downloadable for free. Some applications designed for Windows can also be run on Linux using emulators and other means. Note that in terms of loopholes for hackers there are literally thousands of people working with Linux and potential entry points for hackers are resolved very quickly, with free dissemination of the updates to other Linux users. It also appears that free Linux applications are Microsoft compatible and can read Word and other documents, while one user I know claims that a Photoshop equivalent (that is written for Linux) is far superior to the original Photoshop, and it is totally free!
With all the developments in terms of Linux it is available in many formats (many developed for specific applications) called distributions. Some of these are free and for some there is a nominal charge. Distributions available cover all possible applications including administration, system networking, communication, office and scientific applications etc.
Of course, being effectively free, you can load the OS and software on as many computers as you want and if you have the unfortunate experience of having your computers stolen you do not have to purchase another expensive one-user licence. This is an area where Microsoft needs to look at the needs of its customers who today often have a desktop at work and a laptop at home. Many other smaller software vendors have accepted this and allow you to load their software on two systems for home and office compatibility. Note that although Linux is just an operating system there are several major companies including Novell, Monte Vista and Red Hat who do provide Linux products and services. These companies provide complete embedded solutions with ongoing support but their products and services are not in the free public domain and their charges are used to sustain their own ongoing developments. The advantage for the user is that he can buy something off the shelf and have it up and running in no time. Some companies offer an alternative to paying up front, the cost being paid on a subscription basis with regular updates. There are a number of small Linux solutions available free of charge, but these are usually based on older kernels with small embedded distribution capabilities. Such software would require a Linux expert to install effectively.
Another even less widely known operating system is QNX. This OS has a lean core of highly reliable code and is powerful enough to run a distributed network of several hundred processors with the lower cost of PC-based products rather than high-end solutions. QNX Software Solutions has been in the business for more than 23 years. It was one of the first companies to offer a commercial UNIX derivative on a PC platform, and went on service to the niche realtime and embedded market. Interesting for those with critical applications who do not want software crashes one of the attributes of the QNX OS is its use 'where software failure is not an option'. Like Linux, QNX has a number of strategic partners including IBM and Motorola. Note that QNX does not offer binary compatibility with Linux, but being POSIX compliant, it offers excellent source compatibility. Many software utilities available under Linux are also available under QNX.
The differentiator in terms of QNX is that unlike the monolithic traditional kernel used by its competitors the OS of the software uses a realtime microkernel. According to QNX a microkernel can do anything a monolithic kernel can do but with additional benefits. It lets the system recover gracefully from faults in drivers and it allows system services to be upgraded dynamically. What is more the microkernel allows you to do system level coding and debugging at the process level without having to reboot on each test-debug cycle, offering a major saving in software development time.
In terms of QNX its bulletproof realtime operating system is used in an increasing number of industries where software failure has major consequences. These include telecommunications, industrial automation, medical devices and military equipment. A few years ago QNX entered the automotive market and this sector now accounts for 10% of its business. Unlike Linux, QNX Software Solutions is a 'real' company based in Ottawa, Canada, where it employs some 180 people. The customer base of QNX includes Cisco, Siemens, Sony and defence giant, Thales. Applications include use in hospital emergency rooms, nuclear reactors, high-speed trains and mail sorting machines.
As with Linux, QNX is targeting the embedded market where it sees enormous opportunities for its OS. The company believes that the diversity of applications in this market will ensure true and healthy competition and will make it very unlikely that Microsoft will achieve the more than 90% share that it has in the PC market.
In June this year, DATAC Technologies, known for its secure scada and process automation software, announced the release of its DATAC RealFlex 6 software. This uniquely combines a true realtime multitasking QNX Neutrino operating system with a Windows-based HMI, providing the user with the best of both worlds. The objective of using the QNX OS was to provide greater security and data transfer between the secure QNX-based server and the client's scada applications is dynamically encrypted. DATAC claims that through a close relationship with QNX they are able to create full scada architectures and that the QNX OS is field-proven in thousands of mission critical applications.
Two independent reports were published during 2002, one comparing the QNX RTOS V6.2 with the Red Hat embedded Linux (ELDS) V1.1, and the other comparing QNX, VxWorks and Windows CE.NET. The first report rated QNX highly with the OS performing particularly well in realtime where it picked up every interrupt at 9 µs intervals, while ELDS could only manage 60 µs. While the tools and Internet support were similar, documentation for the ELDS was definitely lacking. In the second report, documentation for all three operating systems was found to be inadequate, but QNX was rated highest in terms of ease of installation and configuration as well as in terms of its RTOS architecture. While Windows CE.NET performs slower than QNX it did exhibit true realtime behaviour. Realtime operation is one of the reasons why QNX is used in critical applications and newer versions of the operating system will be operating in the sub microsecond range.
With regard to the use of Linux and QNX in the South African context, local companies are definitely using the former in security type systems and some customers are asking for Linux-based solutions. Although QNX was originally developed for the automation and control industry it has found application in many other niche applications. Pick 'n Pay, Game and Dion use it for their point of sale applications and it is also used at the SANAE base in Antarctica. There are many other local users and it has established quite a niche for itself in the automotive industry. Overseas, Cisco has standardised on QNX as an embedded operating system.
In the future there is little doubt that Linux, QNX and other operating systems are going to break the hold on the market held by Microsoft. Features of QNX for example that will influence customers include its true realtime operation, its embedded architecture and its scalability. Linux scores heavily in cost if you have people skilled in programming it. For the enthusiast there is a wealth of material available now for Linux with websites, books and magazines seeing its implementation becoming less of a problem every year. Linux single-handedly caused UNIX to be 'sexy', and programmers are rediscovering its elegant and powerful programming 'everything is a file' paradigm developed over decades.
Thanks in regard to the preparation of this article goes to Alex Cellarius of Systems 104 in Pretoria. Besides being an expert in realtime embedded solutions, Alex is also the sole distributor for QNX. The company also sells hardware, in the form of modules and boards for embedded systems, and where these are adapted for a Linux OS (such as the Kontron product range) and purchased from Systems 104, full integration support can be provided. Alex can be contacted at 012 346 5437 or at [email protected]
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Dr Maurice McDowell has many years' experience as a technical journalist, editor, business manager and research scientist. His third party analyses of world-class companies and processes, as well as his insight into industry and technology trends are well respected.
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