The configuration information generation unit 101, when given a set of constituent requirements, generates configuration information representing the system, by repeating operation of replacing the constituent requirement with a set of more concrete constituent requirements according to a replacement rule. The verification program generation unit 106 generates, for each constituent requirement, a verification program for verifying whether parts in the system corresponding to the constituent requirement in the configuration information are normal or not. The verification program execution unit 107 causes the system to execute the verification program. The fault isolation unit 109 separates the part in the system where a fault may have occurred from the part where the fault has not occurred, according to whether execution result of the verification program is success or not.

A synchronous core processing unit executes the same program as a program executed by another computer for an execution unit at a synchronization timing synchronized with a synchronous core processing unit of the other computer, and migrates the program being executed for which migration is requested according to characteristics of the program to a quasi-synchronous core processing unit. The quasi-synchronous core processing unit executes the program migrated from the synchronous core processing unit, and then migrates the program to the synchronous core processing unit. The synchronous core processing unit outputs, to an output comparison machine, an execution result obtained by executing the program migrated from the quasi-synchronous core processing unit at the synchronization timing.

A method tests at least three devices, each device including a test chain having a plurality of positions storing test data. The testing includes comparing test data in a last position of the test chain of each of the devices, and shifting test data in the test chains of each of the devices and storing a result of the comparison in a first position of the test chains of each of the devices. The comparing and the shifting and storing are repeated until all the stored test data has been compared. The at least three devices may have a same functionality and a same structure.

An output control apparatus that controls opening and closing between an output terminal connected to an external apparatus and a power supply terminal to which power for the external apparatus is supplied is provided. The output control apparatus includes a first switching element and a second switching element that are connected in series between the power supply terminal and the output terminal, a data generation portion that generates output data for turning on and off the first switching element and the second switching element based on a control command received from outside, a first controller that controls drive of the first switching element, and a second controller that controls drive of the second switching element.

An output control apparatus that controls opening and closing between an output terminal connected to an external apparatus and a power supply terminal to which power for the external apparatus is supplied is provided. The output control apparatus includes a first switching element and a second switching element that are connected in series between the power supply terminal and the output terminal, a data generation portion that generates output data for turning on and off the first switching element and the second switching element based on a control command received from outside, a first controller that controls drive of the first switching element, and a second controller that controls drive of the second switching element.

The voter circuit and method determines a voted output among plural inputs each carrying circular data. To supply the voted output, a statistical average (e.g., mean or median) is computed by grouping the plural inputs into pairs, and for each pair generating a minimum angular difference by selecting the minimum of (a) the absolute difference between the pairs of inputs, and (b) the conjugate of the absolute difference between the pairs of inputs. The voted output is a statistical average generated from the minimum angular difference.

A quorum in a cluster of nodes in a quorum-based computing system can be dynamically updated such that even just a single remaining operational node can be sufficient to support continued operation of the computing system, while other node(s) in the cluster are in a failure state. When the other node(s) in the cluster become enabled again, the quorum can be adjusted back to an original quorum of the cluster. The content of storage devices in such other node(s) can be deleted when the node(s) start up from the failure state, and up-to-date content from the operational node can be synchronized into the newly started other node(s), thereby enabling content to be consistent and updated in all of the operational nodes in the cluster/quorum.

An apparatus comprises at least one processing device that includes a processor coupled to a memory. The processing device is configured to associate a first storage node with at least a second storage node in a plurality of storage nodes of a distributed storage system, each such storage node comprising a plurality of storage devices, to establish a storage devices group comprising specified ones of the storage devices of the first and second storage nodes, to detect an issue with a first communication channel to the first storage node, and responsive to the detected issue, to communicate with the first storage node via the second storage node, utilizing an alternative communication channel involving one or more storage devices of the storage devices group. The storage devices group may comprise a designated subset of storage devices within a common disk array enclosure (DAE) shared by the first and second storage nodes.

A system includes a parallel redundancy protocol (PRP) link redundancy entity (LRE) configured to receive data and copy the data to create a first copy of the data and a second copy of the data for transmission and a switch configured to cause operation between a first PRP media access control security (MACsec) mode and a second PRP MACsec mode to encrypt the data. The first PRP MACsec mode includes performing MACsec encryption on the data received by the PRP LRE prior to the data being copied by the PRP LRE, and the second PRP MACsec mode includes performing the MACsec encryption on the first copy of the data and the second copy of the data after the data has been copied by the PRP LRE.

A method and system for performing a flexible Byzantine fault tolerant (BFT) protocol. The method includes sending, from a client device, a proposed value to a plurality of replica devices and receiving, from at least one of the plurality of replica devices, a safe vote on the proposed value. The replica device sends the safe vote, based on a first quorum being reached, to the client device and each of the other replica devices of the plurality of replica devices. The method further includes determining that a number of received safe votes for the proposed value meets or exceeds a second quorum threshold, selecting the proposed value based on the determination, and setting a period of time within which to receive additional votes. The method further includes, based on the period of time elapsing without receiving the additional votes, committing the selected value for the single view.