Abstract: Disclosed are various embodiments for distributing data items. A plurality of nodes forms a distributed data store. A new master candidate is determined through an election among the plurality of nodes. Before performing a failover from a failed master to the new master candidate, a consensus is reached among a locality-based failover quorum of the nodes. The quorum excludes any of the nodes that are in a failover quorum ineligibility mode.

Abstract: A solar panel window assembly for an aircraft and method of forming such assembly includes an outer window panel and an inner window panel mounted in a window frame structure. The window frame structure holds the outer window panel spaced from and parallel to the inner window panel. A solar panel is mounted on an inner surface of the window frame structure between the outer window panel and the inner window panel. A foam kit may be mounted between the solar panel and the window frame structure. The inner window panel may be an electrically dimmable window panel. The solar panel may be coupled to power the electrically dimmable window panel. In addition, an alternative solar panel window assembly includes a window plug assembly adapted to fit into a window aperture in an aircraft and a solar panel mounted on an outer surface of the window plug assembly.

Abstract: A solar panel window assembly for an aircraft and method of forming such assembly includes an outer window panel and an inner window panel mounted in a window frame structure. The window frame structure holds the outer window panel spaced from and parallel to the inner window panel. A solar panel is mounted on an inner surface of the window frame structure between the outer window panel and the inner window panel. A foam kit may be mounted between the solar panel and the window frame structure. The inner window panel may be an electrically dimmable window panel. The solar panel may be coupled to power the electrically dimmable window panel. In addition, an alternative solar panel window assembly includes a window plug assembly adapted to fit into a window aperture in an aircraft and a solar panel mounted on an outer surface of the window plug assembly.

Abstract: A drilling head for a tubular shank having an inside diameter and threads may comprise an axial body comprising a duct exiting through a first end; threads adjacent the first end corresponding to the threads on the shank and aligning the duct with the shank inside diameter; a bore from an outer surface of the body to the duct; and two axially extending approximately parallel and offset surfaces adjacent a second end; and an insert affixed between the offset surfaces, the insert comprising: a first face at least partially contacting one offset surface and a second face at least partially contacting the other offset surface; one or more cutting edges adjacent the first face, the second face, or both; and a cutting lip adjacent one or more cutting edges.

Abstract: Disclosed are various embodiments for distributing data items. A plurality of nodes forms a distributed data store. A new master candidate is determined through an election among the plurality of nodes. Before performing a failover from a failed master to the new master candidate, a consensus is reached among a locality-based failover quorum of the nodes. The quorum excludes any of the nodes that are in a failover quorum ineligibility mode.

Abstract: Techniques for producing a gentle reduction in throughput in a distributed service when a node of the service encounters a very large backlog of requests and/or when a previously offline node of the service is brought back online. These techniques may utilize multiple different algorithms to determine an amount of work that the distributed service is able to accept at any given time, rather than a single algorithm.

Abstract: Disclosed are various embodiments for distributing data items. A plurality of nodes forms a distributed data store. A new master candidate is determined through an election among the plurality of nodes. Before performing a failover from a failed master to the new master candidate, a consensus is reached among a locality-based failover quorum of the nodes. The quorum excludes any of the nodes that are in a failover quorum ineligibility mode.

Abstract: A drilling head for a tubular shank having an inside diameter and threads may comprise an axial body comprising a duct exiting through a first end; threads adjacent the first end corresponding to the threads on the shank and aligning the duct with the shank inside diameter; a bore from an outer surface of the body to the duct; and two axially extending approximately parallel and offset surfaces adjacent a second end; and an insert affixed between the offset surfaces, the insert comprising: a first face at least partially contacting one offset surface and a second face at least partially contacting the other offset surface; one or more cutting edges adjacent the first face, the second face, or both; and a cutting lip adjacent one or more cutting edges.

Abstract: A drilling head for a tubular shank having an inside diameter and threads may comprise an axial body comprising a duct exiting through a first end; threads adjacent the first end corresponding to the threads on the shank and aligning the duct with the shank inside diameter; a bore from an outer surface of the body to the duct; and two axially extending approximately parallel and offset surfaces adjacent a second end; and an insert affixed between the offset surfaces, the insert comprising: a first face at least partially contacting one offset surface and a second face at least partially contacting the other offset surface; one or more cutting edges adjacent the first face, the second face, or both; and a cutting lip adjacent one or more cutting edges.

Abstract: A system that implements a data storage service may store data on behalf of storage service clients. The system may maintain data in multiple replicas of various partitions that are stored on respective computing nodes in the system. The system may employ a single master failover protocol, usable when a replica attempts to become the master replica for a replica group of which it is a member. Attempting to become the master replica may include acquiring a lock associated with the replica group, and gathering state information from the other replicas in the group. The state information may indicate whether another replica supports the attempt (in which case it is included in a failover quorum) or stores more recent data or metadata than the replica attempting to become the master (in which case synchronization may be required). If the failover quorum includes enough replicas, the replica may become the master.

Abstract: A system that implements a data storage service may store data on behalf of storage service clients. The system may maintain data in multiple replicas of partitions that are stored on respective computing nodes in the system. A master replica for a replica group may increment a membership version indicator for the group, and may propagate metadata (including the membership version indicator) indicating a membership change for the group to other members of the group. Propagating the metadata may include sending a log record containing the metadata to the other replicas to be appended to their respective logs. Once the membership change becomes durable, it may be committed. A replica attempting to become the master of a replica group may determine that another replica in the group has observed a more recent membership version, in which case logs may be synchronized or snipped, or the attempt may be abandoned.

Abstract: A system that implements a scalable data storage service may maintain tables in a data store on behalf of storage service clients. The service may maintain table data in multiple replicas of partitions that are stored on respective computing nodes in the system. In response to detecting an anomaly in the system, detecting a change in data volume on a partition or service request traffic directed to a partition, or receiving a service request from a client to split a partition, the data storage service may create additional copies of a partition replica using a physical copy mechanism. The data storage service may issue a split command defined in an API for the data store to divide the original and additional replicas into multiple replica groups, and to configure each replica group to maintain a respective portion of the table data that was stored in the partition before the split.

Abstract: A system that provides services to clients may receive and service requests, various ones of which may require different amounts of work. An admission control mechanism may manage requests based on tokens, each of which represents a fixed amount of work. The tokens may be added to a token bucket at rate that is dependent on a target work throughput rate while the number of tokens in the bucket does not exceed its maximum capacity. If at least a pre-determined minimum number of tokens is present in the bucket when a service request is received, it may be serviced. Servicing a request may include deducting an initial number of tokens from the bucket, determining that the amount of work performed in servicing the request is different than that represented by the initially deducted tokens, and deducting additional tokens from or replacing tokens in the bucket to reflect the difference.

Abstract: A system that implements a data storage service may store data on behalf of storage service clients. The system may maintain data in multiple replicas of partitions that are stored on respective computing nodes in the system. The system may split a data partition into two new partitions, and may split the replica group that stored the original partitions into two new replica groups, each storing one of the new partitions. To split the replica group, the master replica may propagate membership changes to the other members of the replica group for adding members to the original replica group and for splitting the expanded replica group into two new replica groups. Subsequent to the split, replicas may attempt to become the master for the original replica group or for a new replica group. If an attempt to become master replica for the original replica group succeeds, the split may fail.

Abstract: A system that provides services to clients may receive and service requests, various ones of which may require different amounts of work. The system may determine whether it is operating in an overloaded or underloaded state based on a current work throughput rate, a target work throughput rate, a maximum request rate, or an actual request rate, and may dynamically adjust the maximum request rate in response. For example, if the maximum request rate is being exceeded, the maximum request rate may be raised or lowered, dependent on the current work throughput rate. If the target or committed work throughput rate is being exceeded, but the maximum request rate is not being exceeded, a lower maximum request rate may be proposed. Adjustments to the maximum request rate may be made using multiple incremental adjustments. Service request tokens may be added to a leaky token bucket at the maximum request rate.

Abstract: A system that implements a data storage service may store data on behalf of clients in multiple replicas on respective computing nodes. The system may employ an external service to select a master replica for a replica group. The master replica may service consistent read operations and/or write operations that are directed to the replica group (or to a data partition stored by the replica group). The master replica may employ a quorum based mechanism for performing replicated write operations, and a local lease mechanism for determining the replica authorized to perform consistent reads, even when the external service is unavailable. The master replica may propagate local leases to replica group members as replicated writes. If another replica assumes mastership for the replica group, it may not begin servicing consistent read operations that are directed to the replica group until the lease period for a current local lease expires.

Abstract: A drilling head for a tubular shank having an inside diameter and threads may comprise an axial body comprising a duct exiting through a first end; threads adjacent the first end corresponding to the threads on the shank and aligning the duct with the shank inside diameter; a bore from an outer surface of the body to the duct; and two axially extending approximately parallel and offset surfaces adjacent a second end; and an insert affixed between the offset surfaces, the insert comprising: a first face at least partially contacting one offset surface and a second face at least partially contacting the other offset surface; one or more cutting edges adjacent the first face, the second face, or both; and a cutting lip adjacent one or more cutting edges.

Abstract: A drilling head for a tubular shank having an inside diameter and threads may comprise an axial body comprising a duct exiting through a first end; threads adjacent the first end corresponding to the threads on the shank and aligning the duct with the shank inside diameter; a bore from an outer surface of the body to the duct; and two axially extending approximately parallel and offset surfaces adjacent a second end; and an insert affixed between the offset surfaces, the insert comprising: a first face at least partially contacting one offset surface and a second face at least partially contacting the other offset surface; one or more cutting edges adjacent the first face, the second face, or both; and a cutting lip adjacent one or more cutting edges.

Abstract: Disclosed are various embodiments for distributing data items within a plurality of nodes. A data item update request is replicated from a master node in a plurality of nodes to a plurality of slave nodes within the plurality of nodes. The replicated data item update request is determined to be locality-based durable. Responsive to the determination that the replicated data item update request is locality-based durable, the data item update request is confirmed to a client, wherein the client had originated the data item update request. Upon failover of the master node to another node within the plurality of nodes, a fault-tolerant failover quorum ensures that all previously confirmed updates are found and recognized by the new master node.

Abstract: A drilling head for a tubular shank having an inside diameter and threads may comprise an axial body comprising a duct exiting through a first end; threads adjacent the first end corresponding to the threads on the shank and aligning the duct with the shank inside diameter; a bore from an outer surface of the body to the duct; and two axially extending approximately parallel and offset surfaces adjacent a second end; and an insert affixed between the offset surfaces, the insert comprising: a first face at least partially contacting one offset surface and a second face at least partially contacting the other offset surface; one or more cutting edges adjacent the first face, the second face, or both; and a cutting lip adjacent one or more cutting edges.