The full-size VXIbus Mainframe is a standard 19 inch rack-mounted powered chassis that houses up to 13 VXI C- or D-size modules. Smaller mainframes are also available for C-size modules. Module positions are designated 0 through 12 left to right. The VXIbus specification covers important mainframe considerations such as cooling, power supply noise,electromagnetic compatibility (EMC) and backplane construction.