VME started development in the early 1980s, and was standardized in 1987 as a computer bus standard for use in embedded applications. It was very widely deployed in a range of industrial, research, semiconductor process control, transport, medical and defense applications worldwide. Many of these applications have migrated to more modern and higher bandwidth architectures. VME continues to be a widely installed architecture, particularly in the defense market.
The VME specification, owned by the VITA standards body, was designed with the aim to specify the electrical and mechanical system characteristics required to design devices that will reliably and unambiguously communicate with other VME boards so that the system architect can optimize cost and/or performance without affecting compatibility. The specification itself establishes a framework for parallel bus computer architectures that can implement single and multiprocessor systems.
Concurrent Technologies VME processor boards support the popular VME64 topology with MBLT transfers for up to 40Mbyte per second transfer rates. Whilst significantly slower than the Gbyte per second transfer rates that are common with modern serial fabric systems like VPX, many VME systems today use the VMEbus interface for basic setup and control and use Gigabit Ethernet connections on the front panel for better performance. It is very easy to set up multiprocessing systems with Concurrent Technologies VME processor boards as they can be configured as the System Controller to provide bus arbitration, a VME master supporting off board accessible memory or a VME slave.
To support the typical defense applications, Concurrent Technologies VME boards are designed and tested to operate in and withstand a number of harsh environmental factors including: vibration, shock and extended temperature ranges. It is generally easy for a user to swap an old board with a newer one, often with minimal application and configuration changes. Technology transitions are a low risk solution for a mid-life upgrade or life cycle extension much simpler than replacing the whole system with a new architecture. Also, VME can be cost effective for I/O based systems that don’t need high throughput transfers.