Abstract: The present invention provides a system and method for promoting a probationary member to a full member in a distributed system. A probationary member includes a process in a distributed system that is intended to be added or intended to replace an existing process in the system. Prior to adding or replacing the probationary member, the probationary member is evaluated based on criteria associated with context information related to the system. Based on the evaluation, the probationary member may be promoted to a full member of the system or eliminated from the system. Therefore, the present invention provides the opportunity to evaluate the probationary member in the system, prior to the probationary member being promoted to a full member of the system. Additionally, the probationary member may be added or replace an existing process in a single view change. Therefore, fault tolerance is maintained when the probationary member is replacing a mirror in a fault-tolerant distributed system.

Abstract: The present invention provides a system and method of detecting a process failure and a network failure in a distributed system. The distributed system includes a plurality of processes, each executing on a host, operable to transmit messages (i.e., heartbeats) to each other on a network. A process in the system is operable to execute a process failure algorithm for detecting failure of a process in the system. The process failure algorithm includes calculating a difference in the period of time to receive a heartbeat from a first processes and a period of time to receive a heartbeat from a second process in the system. If the difference exceeds a process failure threshold, the second process is suspected of failing. A process in the system is also operable to execute a network failure algorithm for detecting failure of a network connecting a plurality of hosts in the system.

Abstract: The present invention provides a system and method of detecting a process failure and a network failure in a distributed system. The distributed system includes at least two processes, each executing on a host, operable to transmit messages (i.e., heartbeats) to each other on a plurality of networks in the distributed system. A process in the system is operable to execute a network failure algorithm for detecting failure of a network in the system. The process failure algorithm includes calculating a difference in the period of time to receive a heartbeat on a first network from a process and a period of time to receive a heartbeat on a second network from the process. If the difference exceeds a network failure threshold, the second network is suspected of failing. A process in the system is also operable to execute a process failure algorithm.

Abstract: The present invention provides a system and method of adjusting a heartbeat timeout utilized for monitoring a process in a distributed system. The distributed system includes a plurality of processes monitoring one another by transmitting messages (i.e., heartbeats) indicative of a process being operational. A first process monitoring a second process is operable to receive one or more heartbeats from the second process in the distributed system. If the first process fails to receive a heartbeat from the second process prior to an expiration of the heartbeat timeout, the second process is suspected of failing. If the first process receives a heartbeat from the second process prior to the expiration of the heartbeat timeout, the first process recalculates the heartbeat timeout. Recalculating the heartbeat timeout includes gradually increasing or decreasing the heartbeat timeout based on a period of time to receive a heartbeat.

Abstract: The present invention provides a system and method for promoting a probationary member to a full member in a distributed system. A probationary member includes a process in a distributed system that is intended to be added or intended to replace an existing process in the system. Prior to adding or replacing the probationary member, the probationary member is evaluated based on criteria associated with context information related to the system. Based on the evaluation, the probationary member may be promoted to a full member of the system or eliminated from the system. Therefore, the present invention provides the opportunity to evaluate the probationary member in the system, prior to the probationary member being promoted to a full member of the system. Additionally, the probationary member may be added or replace an existing process in a single view change. Therefore, fault tolerance is maintained when the probationary member is replacing a mirror in a fault-tolerant distributed system.

Abstract: The present invention provides a system and method of detecting a process failure and a network failure in a distributed system. The distributed system includes a plurality of processes, each executing on a host, operable to transmit messages (i.e., heartbeats) to each other on a network. A process in the system is operable to execute a process failure algorithm for detecting failure of a process in the system. The process failure algorithm includes calculating a difference in the period of time to receive a heartbeat from a first processes and a period of time to receive a heartbeat from a second process in the system. If the difference exceeds a process failure threshold, the second process is suspected of failing. A process in the system is also operable to execute a network failure algorithm for detecting failure of a network connecting a plurality of hosts in the system.

Abstract: The present invention provides a system and method of detecting a process failure and a network failure in a distributed system. The distributed system includes at least two processes, each executing on a host, operable to transmit messages (i.e., heartbeats) to each other on a plurality of networks in the distributed system. A process in the system is operable to execute a network failure algorithm for detecting failure of a network in the system. The process failure algorithm includes calculating a difference in the period of time to receive a heartbeat on a first network from a processes and a period of time to receive a heartbeat on a second network from the process. If the difference exceeds a network failure threshold, the second network is suspected of failing. A process in the system is also operable to execute a process failure algorithm.

Abstract: The present invention provides a system and method of adjusting a heartbeat timeout utilized for monitoring a process in a distributed system. The distributed system includes a plurality of processes monitoring one another by transmitting messages (i.e., heartbeats) indicative of a process being operational. A first process monitoring a second process is operable to receive one or more heartbeats from the second process in the distributed system. If the first process fails to receive a heartbeat from the second process prior to an expiration of the heartbeat timeout, the second process is suspected of failing. If the first process receives a heartbeat from the second process prior to the expiration of the heartbeat timeout, the first process recalculates the heartbeat timeout. Recalculating the heartbeat timeout includes gradually increasing or decreasing the heartbeat timeout based on a period of time to receive a heartbeat.

Abstract: A tire assembly comprising outer and inner tires having at least one vent and one plug is described. The vents and plugs mate in the assembly providing an air tight seal in the bead seal region of the tires. The vents or plugs permit air to escape from the outer tire if an attempt is made to mount the outer tire on a rim without a mating inner tire.

Abstract: A device (20) for retaining the beads of a tire against the flanges of a rim. The bead retainer device (20) is capable of being manufally deformable in the axial direction. The bead retainer device is also capable of being manually deformable in the circumferential direction such as to be collapsible.

Abstract: The tread reinforcing belt structure (24) of a pneumatic tire (10) has at least one belt ply (29) of flat steel wire. The belt ply of flat steel wire is stiffened by other components of the tread reinforcing structure such as belt plies of steel cables (28,30). It is especially important that the axially outermost edge portions of the belt ply of flat steel wires be supported by other components of the tread reinforcing belt structure, and that the flat wire have specific cross-sectional dimensions.