Abstract: A read request of a sequential media from a host is executed with a read request data block size equal to a maximum recorded data block size parameter of the variable data block size storage device. Subsequently, if warranted, an adaptive read ahead data block size variable is set to equal a recorded data block size of data recorded on the sequential media that is responsive to the execution of the read request, and one or more read ahead requests of the sequential media are executed with a read ahead data block size equal to the adaptive read ahead data block size variable.

Abstract: Within a distributed data processing domain including a requester data processing node and one or more target data processing nodes, an update synchronization of a domain information file as stored on each target data processing node with each domain information file including a local information file having local information an individual operation of the requester data processing node and a global information file having global information associated with a collective operation of all of the data processing nodes. First, the requester data processing node detects domain update information including local update information or global update information. Second, the requester data processing node synchronizes an update of the local information file or the global information file of each domain information file as stored on the target data processing node(s) based on the respective local update information or the respective global update information of the detected domain update information.

Abstract: In a distributed data processing domain including a plurality of data processing nodes, a simulation data processing node is operated as a participant in a simulation testing of a node operation to determine a simulation job and a simulation command responsive to the simulation testing of the node operation. The simulation job is indicative of one or more actions to be performed by the simulation data processing node as a function of the simulation testing of the node operation, and the simulation command is indicative of a message format for a simulated message representative of simulation job, whereby the simulation data processing node builds the simulated message based on the simulation job and the simulation command.

Abstract: Computer systems, logging daemons, methods, and computer program products are provided for logging information from a plurality of logging applications regarding the computer system. A registry is configured to identify the logging applications, and the plurality of logging applications are configured to identify the logged information in accordance with a common protocol and in accordance with the registry. A logging control is configured to parse the logged information, and configured to save the logged information in accordance with the parsing.

Abstract: An apparatus, system, and method are disclosed for recovering a message from a failed node. A message module communicates a message to a request queue and a copy queue. A transfer module transfers the message from the request queue to a first target node in response to the message residing in the request queue. A detection module detects a failure of the first target node. A recovery module copies the message from the copy queue to the request queue in response to the failure of the first target node and the message residing in the copy queue. The transfer module further transfers the message from the request queue to a second target node in response to the message residing in the request queue.

Abstract: A system and method for performing a search operation within a sequential access data storage subsystem are disclosed. According to one embodiment, a data storage subsystem is provided which comprises a search module and a communication channel interface to communicatively couple the data storage subsystem to a host data processing system via a communication channel. In the described embodiment, the search module is configured to receive search attribute data from the host data processing system via the communication channel interface, where the search attribute data specifies a search attribute. The search module is further configured to perform a search operation on data of a sequential access storage element utilizing the search attribute and to provide search result data to the host data processing system via the communication channel interface in response to a performance of the search operation.

Abstract: A storage subsystem employs one or more device controllers for controlling a plurality of devices. At the request of a host, a device controller controls a writing of data from the host to device including a media mounted in a first drive. In response to a detection of a defect in the device, the device controller controls a swap of the first drive for the second drive, which includes the device controller recovering any first portion of the data buffered in the first drive and/or any second portion of the data recorded on the first media, and writing any recovered first portion of the data and/or any recovered second portion of the data to the second drive.

Abstract: A read request of a sequential media from a host is executed with a read request data block size equal to a maximum recorded data block size parameter of the variable data block size storage device. Subsequently, if warranted, an adaptive read ahead data block size variable is set to equal a recorded data block size of data recorded on the sequential media that is responsive to the execution of the read request, and one or more read ahead requests of the sequential media are executed with a read ahead data block size equal to the adaptive read ahead data block size variable.

Abstract: A data storage and retrieval system which includes encoded information regarding known valid system configurations, nominal performance specifications for various I/O devices, and nominal performance specifications for various interconnecting communication buses. A method to validate the apparent configuration of Applicants' system. A method to evaluate the performance of each I/O device and interconnecting bus disposed within Applicants' system.

Abstract: The present invention provides fast read performance for accessing a file from a multiplicity of files when its corresponding Block ID is unavailable, by furnishing new file-positioning commands, allowing access to data based on File Number, at the same fast locate speed as with Block Ids, thereby expanding the range of applications that can use certain tape drive systems effectively. The present invention includes both a device architecture for supporting the file oriented positioning and the appending, as well as a software system that can permit easy application access to the device facilities and system components which permit the advantages to accrue without any software application or operator changes, including a robust architecture for navigating residual data, e.g., for data recovery. The present invention comprises several device command innovations, a relative positioning command, an absolute positioning command, and other commands, e.g., for sensing current position.

Abstract: The process, apparatus, and system estimate the size of a data block in a data buffer to efficiently recover the data block to the memory of a computer. The data block resides in a data buffer prior to being written to a destination medium. If the data block cannot be written to the destination medium, the process, apparatus, and system create a data block size estimate. The data block size estimate may be based on the size of the largest data block in the data buffer. Alternately, the data block size estimate may be based on the size of a data block in the memory of the computer. The computer reserves a memory space proportional to the data block size estimate and recovers the data block to the memory space.

Abstract: An apparatus, system, and method are provided for communicating control messages between a first device and a second device. The apparatus, system, and method include a communication module that directs control messages between a first device and a second device through an intermediate device. The intermediate device is coupled to the first device by a control path and to the second device by a data path. The apparatus, system, and method also include a translation module and a transmission module that cooperate to translate control messages received over the control path at the intermediate device to transport data messages and transport data messages received over the data path at the second device to control messages. Transport data messages are sent over the data path to the second device and control messages from the second device are sent over the control path to the first device.