These advanced strategies often involve adopting virtualization technology as a means for minimizing the impact that software changes can have on their automated processes. At Petronas, the goal is to be able to make upgrades without breaking the bank and disrupting the flow of 1,000 million standard cubic feet of gas produced there per day.
Since June, one of the plant’s four operating units has been running the Experion Virtualization Solution from Honeywell Process Solutions. Installation on the remaining three units is underway.
The move at Petronas is largely a response to the steady trend away from proprietary control systems. Open systems have accelerated change in industries where change has traditionally been relatively slow. “The industry isn’t going to reverse this trend to go back to proprietary systems,” notes Paul Hodge, Honeywell’s virtualization product manager in Australia. “So, users want us automation vendors to reduce the amount of churn and change being imposed as a result of open systems.”
Change can be an expensive undertaking, especially when it involves new hardware. For example, it may require upgrading the operating system. “This, in turn, may require retesting or recertification of existing applications,” says Hodge. “It may also require upgrades of the application software to work with the new hardware.”
Virtualization technology minimizes these costs by using a tool called a hypervisor to abstract the operating system and application from the underlying hardware and to represent physical hardware as virtual devices. The virtual hardware acts as a base layer that is portable across different generations of both x86 platforms and hypervisors. Stability in this virtual layer allows changes in the hardware or hypervisor to be transparent. “For example, an operating system and application will see no change to the virtual hardware that it’s running on as long as the virtual hardware version remains the same,” says Hodge.
Although the virtual hardware has a supported lifecycle, just like physical hardware, that life is much longer and more stable than it is for physical hardware. Hodge estimates the typical lifecycle to be at least 10 years for a given version of virtual hardware.
The design of the hypervisor is key to keeping maintenance low. For this reason, Honeywell uses the hypervisor from VMware Inc. of Palo Alto, Calif. “It has a very clean separation between virtual hardware and the base hypervisor,” says Hodge. “This is in contrast with other hypervisor designs, in which there is an overlap between the hypervisor and the virtual machine itself.” Consequently, upgrades to the hypervisor could require retesting and revalidating of the virtual machines.
>> Read Automation World's complete coverage, Taking Charge of Code Change