1. In a fault tolerant multiple computer system wherein the multiple computer system is capable of executing, in a coordinated manner, a predetermined set a task in response to inputs from external sources to produce an output to at least one external device, and wherein each computer includes an application computer capable of executing a subset of the predetermined set of tasks, and wherein the subset of tasks for each computer is different, and contains at least one predetermined input/output task for inputting new data from an external source or outputing data to the at least one external device, an operations controller for each computer in the system for selecting the tasks to be executed by the associated applications computer and for sending messages to every other computer; said messages including task selected messages identifying the tasks it has selected, task data valve messages containing the values of the data variables resulting from the tasks executed by its applications computer, and error messages containing the identification of the computers which sent messages having detected errors, each operations controller comprising: fault handler means responsive to messages received from all the computers in the system for checking each message received to identify faulty messages, to record as faulty in a fault state table the computers sending messages identified as being faulty, and to record as faulty in said same fault state table each computer identified as being faulty in said error messages received from a predetermined number of other computers, for passing on for further processing the error-free messages received from non-faulty computers and for sending said error messages to the other computers identifying each computer it has recorded to be faulty in said fault state table; scheduler means storing said subset of tasks in their order of priority and their execution status in response to the error-free task selected and data value messages passed by the fault handler for selecting for execution from said stored subset of tasks said input/output task at predetermined intervals and for selecting in the interval between the selection of said input/output tasks the highest priority unselected task ready for execution, for generating a dispatch signal identifying the task selected for execution, and for sending said task selected messages to all of the computers identifying the tasks it has selected for execution; and task communicator means interfacing said scheduler means and the associated applications computer for storing the values of the data variables contained in the error-free data value messages passed by the fault handler, for assembling the values of the data variables required for the execution of the selected task in response to said dispatch signal, for sending to the applications computer the assembled values of the data variables in response to the applications computer signifying it has completed the previous task, for sending to all of the computers data value messages containing the values of the data variables resulting from the execution of the selected task by the associated applications computer and for receiving from said external sources and sending to said at least one external device the data values resulting from the execution of said input/output task.