Embedded Virtual Manager on Multi-Core Solves Legacy RTOS Problems
Starting from scratch is a luxury many embedded developers cannot afford. Building solutions on a base of existing proven software is often the fastest and most reliable road to success. But how does one add features to existing proven real-time software without disturbing the underlying reliability and performance of that legacy software?
A History of Real-Time for Windows
In 1997 TenAsys Corporation introduced INtime®, an RTOS that provides hard real-time determinism alongside Microsoft® Windows® on a single embedded PC. A unique form of virtualization makes this possible, letting Windows run unmodified as the lowest priority task in the system. This “real-time Windows platform” has provided hundreds of developers the means to build deterministic embedded Windows systems that reliably control critical machine functions and simultaneously include high-level interfaces for system monitoring, enterprise connectivity, and complex user interaction.
Using Intel® Virtualization Technology (Intel® VT) TenAsys now offers the eVM™ platform, an embedded virtual machine manager (VMM) capable of supporting the demands of a variety of embedded operating systems while simultaneously hosting the Windows OS, each on dedicated cores of a multi-core processor. This has very useful implications for applications that need to preserve legacy real-time code.
An Embedded VMM for Real-Time
The eVM platform facilitates migrating legacy embedded code from obsolete hardware to modern embedded platforms. Legacy I/O can be virtualized and redirected to minimize rewriting proven software. For example, an obsolete ISA system can be migrated to a smaller and less expensive single-board computer by redirecting access to ISA peripherals to equivalent on-board PCI devices.
Traditional VMM software emulates an entire machine, giving each guest OS what it thinks is control of the hardware. Direct access to real I/O, particularly specialized I/O, is a key requirement of embedded software. A traditional VMM does not provide direct and unfettered access to the underlying physical I/O.
Multi-Core Intel® Processors Support Real-Time Virtualization
The TenAsys eVM utilizes multi-core Intel VT processors to host virtually any OS, both legacy and current, alongside Microsoft Windows. In an eVM system, resources are partitioned, insuring each OS has direct access to time-critical hardware that would be restricted or denied by a traditional VMM. Assigning I/O exclusively, and dedicating CPU core(s) to an OS, is essential to guaranteeing determinism.
Determinism and the priority of real-time tasks are fundamental requirements for an RTOS; hosting an RTOS on the eVM platform does not dilute those requirements. Partitioning resources insures that only the authorized OS will have direct access to its time-critical I/O, with little or no overhead from the VMM.
The net gains from the application of virtualization technology on Intel multi-core processor platforms are the elimination of redundant computer and communication hardware, faster communication and coordination between RTOS and Windows subsystems, improved reliability and robustness, re-use of proven legacy applications, and simplified development and debugging. Systems that previously required multiple discrete computing modules can be combined onto a single hardware platform, saving costs in design, manufacturing, and maintenance.