Linux has long been on the “wishlist" for control systems. Until now, most systems have been locked-in to the Windows operating system due to reliance on classic OPC—a ubiquitous communication standard based on Microsoft’s Distributed Component Object Model (DCOM). The name of the game is changing, however, with the arrival of the next-generation OPC standard, the OPC Unified Architecture (OPC-UA). The new standard was designed for cross-platform compatibility, which makes room for Linux to gain popularity in the automated control industry.
Jonathan Gross, vice president of Pemeco, a 32-year-old IT consulting firm, explained why Linux will be a big player as the industry moves ahead. “The stars are aligned for Linux-powered servers to gain significant market-share in industrial automation environments,” Gross said. “Currently, security, stability and reliability make Linux the operating system of choice to support many web-server applications. With the increasing tendency to develop SCADA and control systems in web-based environments, it only makes sense that end-users will strongly consider Linux-based operating platforms. As icing-on-the-cake, Linux generally has a much lower total cost of ownership than Windows.”
Gross is not alone in his analysis. Others in the industry, such as Paresh Dalwalla, are also predicting a growing trend toward Linux. Dalwalla is president of OpteBiz Inc., which focuses on providing real-time operational intelligence solutions to control system users in both the United States and India.
Dalwalla’s explanation closely mirrors that of Gross. “End users are looking for improved security, stability, and reduced total cost of ownership,” Dalwalla said. “More and more end users will see the benefits once they cross the learning curve of an open source operating system. This change will require some time and commitment, but it will be well worth the effort.”
Let’s look at why security, stability, and cost top the list of reasons why Linux is a great choice for control systems.
Reason #1: Security
If a computer system's integrity is compromised by a virus or a malicious attacker exploiting a security vulnerability, it can cause downtime and equipment damage. Just this week, Managing Automation magazine published a story regarding a virus that attacks the Siemens’ SIMATIC WinCC and PCS7 software through a vulnerability in Windows. The article also states that these types of attacks for process control systems have been on the rise during the past few years. (Editor's note: Update from Siemens on Virus affecting Simatic WinCC SCADA systems)
Until recently, companies were tied to Windows as the base for their control system—and they were more likely to be a victim of system hacking than if they were using Linux.
“Compared to Linux, Windows is a bigger attack target,” Gross said. “On average, Windows operating systems are roughly twice as susceptible to hacks and cyber-attacks. Also, an attack event on a Windows operating system has the potential to cause more widespread damage than a similar attack on a Linux system.”
Using Linux means less vulnerability, less downtime, and fewer headaches for companies.
Reason #2: Stability and Reliability
Linux is widely considered to crash less than Windows. It’s also easier to update the system without having to reset the system, as is needed in a Windows environment. This means that systems have more uptime and increased productivity levels.
“Operating system or server downtime introduces risks associated with a temporary inability to monitor and control the systems,” explains Gross. "Though today’s Windows systems are much more stable than they have historically been, they still experience more downtime than Linux systems. One reason for downtime is that Windows systems need to be rebooted to install updates. In contrast, Linux systems can generally be updated without a hardware reset.”
Reason #3: Less Cost
Last but definitely not least is the fact that Linux is more cost effective in the long run. Not only is it available free of cost because it’s open source, but it’s also easier to maintain by IT staff—which means substantial savings in ongoing administrative costs.
“The open source market has expanded tremendously in recent times due to the backing of large companies such as Sun and Google,” Dalwalla said. “Linux is an open source operating system that is considered more stable and comes with very little capital costs. There are ongoing support costs that are to be considered for both options, but Linux can definitely help keep it down.”
Bottom line, companies don’t have to spend money on licenses for Windows servers, nor spend as much time maintaining the system.
OPC-UA and Linux in Action
Now that OPC-UA is available, the next step to take is to find products that use the new standard. Integrator Kyle Chase described his story. Chase is a systems integration specialist for Surefire SCADA Inc., located in Canada, who has always been a fan of Linux. Naturally, he was very excited about OPC-UA and being able to build systems on Linux.
Earlier this year, Chase found Ignition by Inductive Automation, which included an OPC-UA server, making the entire software system Linux compatible. Having used Inductive Automation software for the past three years with much success, he was confident in trying out the company’s newest release.
He gave an example of a project he implemented for a customer using Ignition. The customer’s distillation refinery has a single controller with 14 racks of remote IO. The facility needed both fast update performance, as well as reliability. Previous solutions from industry-leaders couldn’t deliver both. For example, one product gave them the reliability, but it could only give updates once every eight seconds—but the customer needed updates every second. Another product they tried provided the performance needed, but it would shut down every day.
Enter Ignition, OPC-UA, and access to Linux. Chase began testing to see how well it performed, and after going through dry runs, he has been very pleased.
“The performance is absolutely crazy!” Chase said. “Ignition is actively subscribed to 30,000 tags with updates every second. We can finally monitor all of our tags, at the speed we want with the reliability we need.”
Chase is sold on OPC-UA. “To me, the move to a true cross platform environment is important,” he stated. “This holds many advantages, especially when it comes to system flexibility and security. It helps keep costs down as well. Inductive Automation is the first to provide the software required to do this.”