A high availability computer system and methodology including a backplane, having at least one backplane communication bus and a diagnostic bus, a plurality of motherboards, each interfacing to the diagnostic bus. Each motherboard also includes a memory system including main memory distributed among the plurality of motherboards and a memory controller module for accessing said main memory interfacing to said motherboard communication bus. Each motherboard also includes at least one daughterboard, detachably connected to thereto. The motherboard further includes a backplane diagnostic bus interface mechanism interfacing each of the motherboards to the backplane diagnostic bus; a microcontroller for processing information and providing outputs and a test bus controller mechanism including registers therein. The system further includes a scan chain that electrically interconnects functionalities mounted on each motherboard and each of the at least one daughter board to the test bus controller; and an applications program for execution with said microcontroller. The applications program including instructions and criteria to automatically test the functionalities and electrical connections and interconnections, to automatically determine the presence of one or more faulted components and to automatically functionally remove the faulted component(s) from the computer system. Also featured is a balanced clock tree circuit that automatically and selectively supplies certain clock pulses to the logical flip/flops of an ASIC. The system further includes redundant clock generation and distribution circuitry that automatically fails to the redundant clock circuitry in the event of a failure of the normal clock source.