Abstract: Server computers often include one or more input/output (I/O) devices for communicating with a network or directly attached storage device. Data transferred between these devices may include blocks of data with a common often repeated and identifiable data pattern. Transfer and storage of data of this nature may be optimized by transferring primarily blocks of data that are not of the pre-determined data pattern. An indicator may be transferred and stored with transferred data that has been reduced in size in this manner.

Abstract: The present disclosure provides persistent storage for a master copy using operation numbers. A master copy can include a B-tree with references to corresponding data. When provisioning a slave copy, the master copy sends a point-in-time copy of the B-tree to the slave copy, which stores a copy of the B-tree, allocates the necessary space, and updates the references of the B-tree to point to a local storage before the data is transferred. When writing the data to persistent storage, a snapshot created on the master copy is an operation that is replicated to the slave copy. The snapshot is generated using a volume view that includes changes to chunks of data of the master copy since a previous snapshot, as determined using the operation number for the previous snapshot. Data (and metadata) for the snapshot is written to persistent storage while new I/O operations are processed.

Abstract: A slave storage is provisioned using metadata of a master B-tree and updates to references (e.g., offsets) pertaining to data operations of the master B-tree. Master-slave pairs can be used to provide data redundancy, and a master copy can include the master B-tree with references to corresponding data. When provisioning a slave copy, the master sends a B-tree copy to the slave, which stores the slave B-tree copy, allocates the necessary space on local storage, and updates respective offsets of the slave B-tree copy to point to the local storage. Data from the master can then be transferred to the slave and stored according to a note and commit process that ensures operational sequence of the data. Operations received to the master during the process can be committed to the slave copy until the slave is consistent with the master and able to take over as master in the event of a failure.

Abstract: Server computers often include one or more input/output (I/O) adapter devices for communicating with a network or directly attached storage device. The data transfer latency for request can be reduced by utilizing ingress data placement logic to bypass the processor of the I/O adapter device. For example, host memory descriptors can be stored in a content addressable memory unit of the I/O adapter device to facilitate placement of requested data.

Abstract: Burst throttling methods may be used to manage computing resources of a data storage service. Tokens may represent I/O operations executed by a customer of the data storage service. A first token bucket may contain a set of tokens representing the overall I/O operation capacity of the data storage service. Additionally, a second token bucket may contain a set of tokens for a given logical volume maintained by the data storage service. When I/O requests are received tokens may be charged the first token bucket and the second token bucket. Furthermore, if there is sufficient capacity, the data storage service may charge a reduced number of tokens to the third token bucket.

Abstract: Persistent storage for a master copy is provided using operation numbers. A master copy can include a persistent key-value store such as a B-tree with references to corresponding data. When provisioning a slave copy, the master copy sends a point-in-time copy of the B-tree to the slave copy, which stores a copy of the B-tree, allocates the necessary space, and updates the references of the B-tree to point to a local storage before the data is transferred. When writing the data to persistent storage, a snapshot created on the master copy is an operation that is replicated to the slave copy. The snapshot is generated using a volume view that includes changes to chunks of data of the master copy since a previous snapshot, as determined using the operation number for the previous snapshot. Data (and metadata) for the snapshot is written to persistent storage while new EO operations are processed.

Abstract: A slave storage is provisioned using metadata of a master B-tree and updates to references (e.g., offsets) pertaining to data operations of the master B-tree. Master-slave pairs can be used to provide data redundancy, and a master copy can include the master B-tree with references to corresponding data. When provisioning a slave copy, the master sends a B-tree copy to the slave, which stores the slave B-tree copy, allocates the necessary space on local storage, and updates respective offsets of the slave B-tree copy to point to the local storage. Data from the master can then be transferred to the slave and stored according to a note and commit process that ensures operational sequence of the data. Operations received to the master during the process can be committed to the slave copy until the slave is consistent with the master and able to take over as master in the event of a failure.

Abstract: Burst throttling methods may be used manage computing resources of a data storage service. Tokens may represent I/O operations executed by a customer of the data storage service. A global token bucket may contain a set of tokens representing the overall I/O operation capacity of the data storage service. Additionally, a work token bucket may contain a set of tokens for a given logical volume maintained by the data storage service. When I/O request are received tokens may be charged the global token bucket and the work token bucket. Furthermore, if there is sufficient capacity the data storage service may charge a reduced number of tokens to the work token bucket.

Abstract: Burst throttling methods may be used manage computing resources of a data storage service. Tokens may represent I/O operations executed by a customer of the data storage service. A global token bucket may contain a set of tokens representing the overall I/O operation capacity of the data storage service. Additionally, a work token bucket may contain a set of tokens for a given logical volume maintained by the data storage service. When I/O requests are received the data storage service may dynamically determine an amount of tokens to be removed from the global token bucket and/or work token bucket for each received request. Furthermore, if there is sufficient capacity the data storage service may charge a reduced number of tokens to the work token bucket.

Abstract: Burst throttling methods may be used manage computing resources of a data storage service. Tokens may represent I/O operations executed by a customer of the data storage service. A global token bucket may contain a set of tokens representing the overall I/O operation capacity of the data storage service. Additionally, a work token bucket may contain a set of tokens for a given logical volume maintained by the data storage service. When I/O request are received the data storage service may determine if the I/O request is a member of a sequence and removed a reduced number for tokens from the work token bucket as a result. Furthermore, if there is sufficient capacity the data storage service may charge a reduced number of tokens to the work token bucket.

Abstract: A system and method of transporting volumes of information from one host computer system to another using point-in-time copies of LUNs but wherein the hardware provider does not necessarily understand the volume configuration of the data. The system and method involves an intermediate layer, i.e., a point-in-time copy interface layer that communicates with both a requesting host computer system and a hardware provider to enable the transfer of volumes of information without requiring that the hardware provider understand the volume information.

Abstract: A system and method of transporting volumes of information from one host computer system to another using point-in-time copies of LUNs but wherein the hardware provider does not necessarily understand the volume configuration of the data. The system and method involves an intermediate layer, i.e., a point-in-time copy interface layer that communicates with both a requesting host computer system and a hardware provider to enable the transfer of volumes of information without requiring that the hardware provider understand the volume information.

Abstract: A system and method of transporting volumes of information from one host computer system to another using point-in-time copies of LUNs but wherein the hardware provider does not necessarily understand the volume configuration of the data. The system and method involves an intermediate layer, i.e., a point-in-time copy interface layer that communicates with both a requesting host computer system and a hardware provider to enable the transfer of volumes of information without requiring that the hardware provider understand the volume information.

Abstract: A system and method of transporting volumes of information from one host computer system to another using point-in-time copies of LUNs but wherein the hardware provider does not necessarily understand the volume configuration of the data. The system and method involves an intermediate layer, i.e., a point-in-time copy interface layer that communicates with both a requesting host computer system and a hardware provider to enable the transfer of volumes of information without requiring that the hardware provider understand the volume information.

Abstract: An improved operating system for a personal computer including a method for controlling a parallel I/O port for peer-to-peer communication is disclosed. The improved operating system includes a port driver which supports communication with multiple peripheral devices through a single parallel port. The peripheral devices are connect to the parallel port via a multiplexer and may include non-interrupt devices, master/slave devices, and peer-to-peer devices. The parallel port driver includes a port arbitrator and a plurality of class device drivers to control access to the parallel port. Each class device driver communicates with a particular class of devices connected to the port. The port arbitrator controls access to port by the various class device drivers. The parallel port includes configurable control registers that include interrupt control bits for enabling and disabling interrupts communicated by peripheral devices.