In the above example, the continuous data transfers between the disk and the CPU board could be put onto the VSBbus freeing up the VMEbus. The VSBbus uses the A and C rows on the P2 connector to provide for 64 bused signals. Either approach is acceptable. In the past the VSBbus was the most common secondary bus. Raceway is a high performance circuit switched crossbar architecture that is currently undergoing ANSI canvass balloting process.
Additional connections can provide additional bandwidth.
SCSA is oriented to telephony applications such as call processing and focuses not on raw data transfer speed, but on the functional requirements of telephonic voice and facsimile media streams. It provided the means for the implementation of secondary subsystem buses to enhance VMEbus performance. Now new secondary subsystem buses are being developed that will allow the use of VMEbus in a widening range of applications.