Open Kernel Labs is a privately owned company that develops microkernel-based hypervisors and operating systems for embedded systems. The company was founded in 2006 by Steve Subar and Gernot Heiser as a spinout from NICTA. It is headquartered in Chicago, while research and development was located in Sydney, Australia. The company was acquired by General Dynamics in September 2012. Wikipedia.
Heiser G.,University of New South Wales |
Leslie B.,Open Kernel Labs
Proceedings of the 1st ACM Asia-Pacific Workshop on Systems, APSys '10, Co-located with SIGCOMM 2010 | Year: 2010
We argue that recent hypervisor-vs-microkernel discussions completely miss the point. Fundamentally, the two classes of systems have much in common, and provide similar abstractions. We assert that the requirements for both types of systems can be met with a single set of abstractions, a single design, and a single implementation. We present partial proof of the existence of this convergence point, in the guise of the OKL4 microvisor, an industrial-strength system designed as a highly-efficient hypervisor for use in embedded systems. It is also a third-generation microkernel that aims to support the construction of similarly componentised systems as classical microkernels. Benchmarks show that the microvisor's virtualization performance is highly competitive. © 2010 ACM.
Open Kernel Labs | Date: 2012-11-12
The present disclosure provides methods and apparatus for fast context switching in a. virtualized system. In the disclosed system, a globally unique application-space identifier is associated with each guest application. No two applications share the same application-space identifier, even if the two applications reside in different virtual machines. Domain identifiers are used to ensure that a guests mappings are only active when that guest is executing. A unique domain identifier is associated with each virtual machine, and all translation lookaside buffer entries thereby mapping the guests kernel pages with that domain value. All other mappings are tagged with a predefined domain such as zero. In addition, a virtual memory management unit may be configured to support two virtual page table pointers and a configurable boundary between a virtual user page table and a virtual kernel page table. In such an instance, the two virtual page table pointers are presented to a guest operating system, and two physical page table pointers are associated with the two virtual page table pointers.
Open Kernel Labs | Date: 2012-12-07
Methods and apparatus for sharing memory between multiple processes of a virtual machine are disclosed. A hypervisor associates a plurality of guest user memory regions with a first domain and assigns each associated user process an address space identifier to protect the different user memory regions from the different user processes. In addition, the hypervisor associates a global kernel memory region with a second domain. The global kernel region is reserved for the operating system of the virtual machine and is not accessible to the user processes, because the user processes do not have access rights to memory regions associated with the second domain. The hypervisor also associates a global shared memory region with a third domain. The hypervisor allows user processes associated with the third domain to access the global shared region. Using this global shared memory region, different user processes within a virtual machine may share data without the need to swap the shared data in and out of each processes respective user region of memory.
Open Kernel Labs | Date: 2012-12-11
Methods and apparatus for interleaving priorities of a plurality of virtual processors are disclosed. A hypervisor assigns a base priority to each virtual processor and schedules one or more virtual processors to execute on one or more physical processors based on the current priority associated with each virtual processor. When the hypervisor receives an indication from one of the virtual processors that its current priority may be temporarily reduced, the hypervisor lowers the current priority of that virtual processor. The hypervisor then schedules another virtual processor to execute on a physical processor instead of the virtual processor with the temporarily reduced priority. When the hypervisor receives an interrupt for the virtual processor with the lowered priority, the hypervisor raises the priority of that virtual processor and schedules the virtual processor with the restored priority to execute on a physical processor so that processor can handle the interrupt.
News Article | March 21, 2012
IMAGINE a personal computer that has two souls. One moment it is your work machine, complete with a set of corporate applications and tight security settings. Then it becomes an entertainment centre, allowing you to watch any video and download any program. Thanks to a process called “virtualisation”, such computers are now being created. Ever more processing power and clever software are allowing devices of all kinds to separate from their hardware vessels and move to new homes. If this process continues as some expect, it will change computing radically. And more than one IT company will have to rethink how it does business. Virtualisation dates back to the age of mainframe computers. To make better use of them they were sometimes split into smaller “virtual machines”, each of which could run its own operating system and application. But the approach took off only in recent years, when VMWare, a software firm, applied it to servers, the powerful computers that populate today's corporate data centres. VMWare and its main rivals, Citrix and Microsoft, have since developed all kinds of software tools to manage virtual machines—moving them between data centres, for example. The success of server virtualisation has inspired IT firms and their customers to do the same thing with other types of hardware, such as devices to store data. Software now pools their capacity and allocates “virtual disks” as needed. Going further, Dropbox, an online storage service, saves identical files only once. Even large files can take only seconds to upload if they already exist somewhere on one of these firms' disks. The virtualisation of PCs is now under way. Many company computers can already work with applications that run on a central server. But start-ups are pushing the concept further. Desktone offers virtual desktops as an online service. NComputing, a maker of computer terminals, virtualises PCs so they can be shared by up to 30 users. It has already sold more than 2.5m devices, mostly to developing countries and schools. And technology from MokaFive can send an entire virtual machine—complete with operating systems, applications and data—over the network and install it on any PC. Eventually people may no longer need to carry laptops at all. Virtual computers, including data and applications, will follow them everywhere. In the long run, smartphones and other mobile devices may also become shells to be filled as needed. Open Kernel Labs, a start-up in which Citrix has a stake, already lets smartphones run applications, multimedia and radio functions on a single processor, cutting manufacturing costs. Software from Citrix turns the iPad, Apple's tablet computer, into a terminal for applications that run in a corporate data centre. How quickly will virtualisation advance? Gartner, a market-research firm, predicts that the overall market for virtualisation software will grow from $2.7 billion this year to $6.3 billion in 2014. There is certainly no lack of demand. Virtualisation lowers costs by enabling firms to make better use of their servers and buy fewer new ones. The technology also allows PCs to be maintained remotely, which is much cheaper. But improved reliability and security are even more of an attraction. Users of MokaFive, for instance, can relaunch their virtual machine should a computer virus infect it. And it can be shut down if a laptop is lost or stolen. Yet the technology also has to overcome a few hurdles. The virtualisation of servers is well understood, but for PCs and mobile devices the technique has yet to mature. In the longer run institutional barriers will prove more of a problem, argues Simon Crosby, Citrix's chief technology officer. Virtualising IT systems, he says, is only the first step to automating their management. This is seen as a threat to existing workers and makes many IT departments hesitant to embrace the technology. Still, analysts believe virtualisation will win out. Its impact will be felt through the industry. The technology not only makes IT systems more flexible, but allows firms to switch vendors more easily—which will weigh on the vendors' profits. Big software firms such as Microsoft and Oracle may be hit hardest. But many hardware-makers may suffer as well, since their wares will become even more of a commodity than they are today. Moreover, virtualisation makes it much easier to add new servers or storage devices. Alternatively, firms can simply rent extra capacity from operators of what are called “computing clouds”, such as Amazon Web Services. That outfit has built a network of data centres in which virtual machines and disks can be launched in seconds. As a result, IT systems will increasingly no longer be a capital expense, but an operational cost, like electricity. Yet the most noticeable change for computer users will be that more employees will be allowed to bring their own PC or smartphone to work, says Brian Madden of TechTarget, a consultancy. Companies can install a secure virtual heart on private machines, doing away with the need for a separate corporate device. A “bring your own computer” or “BYOC” movement has already emerged in America. Companies such as Citrix and Kraft Foods pay their employees a stipend, which they can use to buy any PC they want—even an Apple Mac. Such innovations may help to ease growing tensions between workers and IT departments. New privacy regulations and rampant cybercrime are pushing firms to tighten control of company PCs and smartphones. At the same time more and more “digital natives” enter the workforce. They have grown up with the freewheeling internet and do not suffer boring black corporate laptops gladly. Giving workers more freedom while helping firms keep control may prove to be the biggest benefit of virtualisation.