An apparatus and method for a computer system is used for implementing an extended distributed recovery block fault tolerance scheme. The computer system includes a supervisory node, an active node and a standby node. Each of the nodes has a primary routine, an alternate routine and an acceptance test for testing the output of the routines. Each node also includes a device driver, a monitor and a node manager for determining the operational configuration of the node. The supervisory node coordinates the operation of the active and standby nodes. The primary and alternate routines are implemented with an application task through a plurality of agent objects operating as finite state machines. A reliable data link extends between the monitors of the active and standby nodes.