Abstract: Disclosed is a bridge system for processing read transactions over a bus in which in a preferred embodiment prefetched data stored in a buffer is not discarded if the address of the requested read does not match the beginning address of the prefetched data. Instead, the bridge system skips to the next address of the prefetched data stored in the buffer and compares that address to the address of the read request to determine if a match exists. If the requested read address does match the next prefetched data address, the prefetched data starting at that next address is read out and forwarded to the requesting agent. Alternatively, if there is not a match, the bridge skips again to the next address and continues checking for a match until either the prefetched data is exhausted or another predetermined limit has been reached. In this manner, many unnecessary data reads of data already prefetched in the buffer may be avoided.

Abstract: A unique combination of four colorants (C′M′Y′K′) of a given printer that is equivalent to an externally defined four colorant combination (CMYK) by having the same color values (e.g., L*a*b* values). A fourth colorant, e.g., black, (K) of the externally defined four colorant combination is mapped to an equivalent fourth colorant (K′) of the printer by matching optical density, reflectance, L* or similar color value. The L* value is found for various percentages of the fourth colorant of the printer by printing varying percentages of the fourth component and measuring its L*a*b* values and, assuming a* and b* are near zero, using the L* value. These values are inputted into an interpolation program. Then, patches of varying percentages of each one of the three color components of the printer (CMY) are printed out at varying percentages.

Abstract: A data processing controlled display system for the interactive display and control of a hierarchical trees of elements or objects in which multiple tree views are presented to the user. The objects in the views are selectable to display detail views of the objects, particularly attributes of the child objects of the selected parent object. The multiple tree views may be of different portions of the same tree or of different trees. The tree views are thus available for side by side comparison and detailed study, after which the system provides the capability to transfer objects from tree view to tree view, e.g. by drag and drop means.

Abstract: Disclosed is a system for handling recall requests for data maintained in storage devices from a host system. The host system maintains a queue of recall requests to a plurality of storage devices. Priority data is associated with each recall request in the queue. The host system initiates a recall operation for a recall request in the queue to a first storage device mounted in a drive. The host system then determines whether a next recall request to the first storage device has a higher priority than a recall request to a second storage device not mounted in a drive. The recall operation for the next recall request to the first storage device is performed after determining that the next recall request has the higher priority. The first storage device is demounted from the drive after determining that the recall request to the second storage device has the higher priority. The second storage device to the drive is mounted after demounting the first storage device from the drive.

Abstract: Disclosed is a system, method, and program for selecting an input/output (I/O) command in a queue of I/O commands. Each I/O command operates within a range of addressable locations on a storage medium. Each addressable location is defined according to a sector number and track number. The program makes use of a plurality of buckets, wherein each bucket represents a range of consecutive sector numbers. Each queued I/O command is associated with a bucket such that a sector number of an addressable location in which an I/O command operates is within the range of sectors comprising the associated bucket. A reference position is determined. A selection routine is then executed to select an I/O command. The selection routine selects a bucket including at least one I/O command and selects an I/O command within the selected bucket. The routine then determines whether the selected I/O command meets a selection criteria. The routine indicates the selected I/O command as the I/O command to process.

Abstract: Disclosed is a system for handling recall requests for data maintained in a storage device accessible to multiple systems. Initially, a storage device is allocated to the first host system to process recall requests in a recall queue including a plurality of recall requests. A second host recall request is initiated with the second host system to recall data from the storage device. The second host system determines whether the storage device is allocated to the first host system. If so, the second host systems stores priority data in a common or shared data structure indicating a priority of the second host recall request after determining that the storage device is allocated to the first host system. The first host system then conditionally releases the storage device before processing all the recall requests needing the subject tape in its queue to make the storage device available if the priority in the common data structure is higher than its own highest priority request.

Abstract: Disclosed is a system for processing program statements, such as statements included in a macro. An assembler program is provided a plurality of statements with an input file. The assembler program processes the statements. For each statement the assembler program determines whether the processed statement is a buffering directive including a statement operand. If the assembler program determines that the processed statement is a buffering directive, the assembler program writes the statement operand of the buffering directive into a memory area. Otherwise, the assembler program generates the processed statement into a data stream. The assembler program generates the statements stored in the memory area into the data stream after processing the statements associated with the macro.

Abstract: Disclosed is a system for managing pages in a volatile memory device for data transfer operations between a first storage area and a second storage area. The first storage area is queried to determine a number of data sets to include in a data transfer operation. A number of pages in the volatile memory device needed for the data transfer operation is then determined. A determination is then made as to whether the number of pages needed for the data transfer operation is greater than available fixed pages in a pool of pages. Available fixed pages in the pool are allocated to the data transfer operation after determining that the number of pages needed to process the data transfer operation is less than or equal to the available fixed pages in the pool.

Abstract: Disclosed is a system for backing up files in a distributed computing system, such as a distributed file system. A backup request is initiated with a backup client program to backup a requested file. A determination is made as to whether the requested file is maintained in a shared name space. The backup client program and a backup server program are capable of accessing files maintained in the shared name space. The file server maintains the files in the shared name space. The backup request is transmitted to the backup server program upon determining that the requested file is maintained in the shared name space. The backup server program transmits a message to the file server to provide the requested file. The file server transmits the requested file to the backup server program. The backup server program stores the requested file in a storage device.

Abstract: Disclosed is a system and method for processing a data access request (DAR). A processing unit, such as a storage controller, receives a DAR, indicating data to return on a channel, such as a channel connecting to a host system, and priority information for the received DAR. The processing unit retrieves the requested data for the received DAR from a memory area, such as a cache or direct access storage device (DASD), and determines whether there is a queue of data entries indicating retrieved data for DARs to transfer on the channel. The queued DARs include priority information. The processing unit processes at least one data entry in the queue, the priority information for the data entry, and the priority information for the received DAR to determine a position in the queue for the received DAR. The processing unit then indicates that the received DAR is at the determined position in the queue and processes the queue to select retrieved data to transfer on the channel to the host system.

Abstract: Disclosed is a system for debugging a computer program. A user indicates a specified breakpoint type, such as a program statement, variable reference, command, etc. The program, including program statements, is then compiled. During compilation, the compiler locates statements in the program corresponding to the breakpoint types and generates a function call into the program at instances in the program of statements corresponding to the user specified breakpoint types. During a debugging phase, a debugger may execute an executable version of the program, including the function calls. Upon processing the function calls, the debugger may stop execution of the program and pass control to the user to perform debugging operations.

Abstract: A storage-and-host-controller-managed outboard data management tool is described wherein the host controller defines logical paths between various storage controllers and data storage devices, and the storage controller manages the movement of data to and from the various data storage devices while only sending data to the host processor if necessary.

Abstract: Disclosed is a system for handling an input/output (I/O) operation. A controller, such as a storage controller, receives an I/O operation against an address for an I/O device, such as a volume in a storage system. The controller determines whether there is at least one active I/O operation executing against the I/O device. After determining that there is at least one active I/O operation, the controller determines whether the received I/O operation conflicts with active I/O operations executing against the I/O device. The controller then executes the received I/O operation against the I/O device concurrently with the active I/O operations after determining that the received I/O operation does not conflict with active I/O operations.

Abstract: A data processing controlled display system for the interactive control of a variety of operations is provided which offers to an operator a plurality of selectable sets of basic interactive functions (i.e. an interactive display interface), each set respectively for the control of one of a plurality of types of operations. There are also provided means for switching a selected first one of said plurality of interactive display interfaces to a selected second one of said display interfaces and means for interactively controlling another one of said production control operations through said second selected interface.

Abstract: Disclosed is a system for indicating whether a group of at least one library element was accessed. The library elements are contained within a housing and are capable of holding storage cartridges. A controller is signaled when an access door of the housing is in an open position. An operator may access the library elements when the access door is in the open position. A motion detector directed toward the group of library elements is activated to detect whether at least one library element in the group was accessed. The motion detector signals the controller upon detecting that at least one library element in the group was accessed. The controller then indicates in a memory area that at least one of the library elements in the group was accessed after the controller is signaled that the access door is in the open position and that at least one library element in the group was accessed.

Abstract: A method, apparatus, and article of manufacture for performing a point-in-time backup using a snapshot function. Work space on a work virtual volume is obtained to hold the snapshot copy of the source data being copied from a source virtual volume. Updates to the source virtual volume are suspended during the snapshot function, so as to provide a logically consistent view of the source virtual volume at a common point in time. Pointers are copied from a virtual track table of the source virtual volume to a virtual track table of the work virtual volume without actually moving any data on data storage devices referenced by those pointers. As a result, the snapshot function provides a method for copying the source virtual volume to the work virtual volume very quickly. Upon completion of the snapshot function, updates to the source virtual volume may be resumed.

Abstract: Disclosed is a system for transferring data involving a data movement, such as the duplication of address information, that includes two data movement components. A first data transfer from at least one source storage location to at least one target storage location is processed. A data structure indicates the source storage locations from which data was transferred during processing of the first data transfer. A second data transfer from a plurality of source storage locations to a plurality of target storage locations is processed. The data structure is then processed to determine the source storage locations included in the second data transfer that were not involved in the first data transfer. Data is then transferred from the source storage locations that were not involved in the first data transfer to the target storage locations that did not receive data during the processing of the first data transfer.

Abstract: The present invention provides a printer system responsive to the request of an operator for performing specified control on a specified portion of a medium during a print operation. Such control minimizes the labor required by an operator to change the set-up condition of the printer when different print media is used. Print operations having modified print attributes for specified areas are set-up for each type of media in advance and stored in a storage device of a printer or a host processor for controlling the printer, such as a personal computer or a server. When a medium is inserted into the printer, medium identifying information, such as a bar coded form number or the size of the medium is used to determine which record stored in the storage device corresponds to the selected medium.

Abstract: Disclosed is a system for indicating system capabilities. A first processing unit, such as a control unit, receives a command from a second processing unit, such as a host system, indicating capabilities of the first processing unit. The first processing unit determines common capabilities indicated in the command that are also available in the first processing unit and indicates in a data structure, such as a bitmap data structure, the common capabilities. The first processing unit then signals the second processing unit of the change in system status.

Abstract: A system and method for increasing capacity utilization of non-volatile storage devices within a group of non-volatile storage devices used to store data from at least one attached system are disclosed. A group of data sets is written to a first storage device as part of a write operation such as migration. A plurality of storage devices partially filled with data are designated as substitutes. The write operation to the first storage device is suspended upon receiving a request to read a data set stored in the first storage device, such as occurs in a recall operation. A second storage device is then selected from the plurality of substitute storage devices. The write operation is continued by writing data sets from the group of data sets included in the write operation that were not written to the first storage device to the selected second storage device. The requested data is then read from the first storage device.