Abstract: A data storage cartridge having an data storage device, such as an encased magnetic disk drive assembly, is, in one embodiment, of generally an exterior dimensional form factor of a tape cartridge having a leader block with a hole therethrough for engagement by a threading pin. To distinguish the cartridge from a tape cartridge, the cartridge shell comprises a blocking portion at the location of the leader block hole. A transfer station both identifies the cartridge and indicates the presence of the cartridge at an end of travel in a cartridge receiver, employing an optical source and an opposed sensor directed toward the leader block hole when a cartridge is at the end of travel. In another embodiment, an encased magnetic disk drive assembly is supported and mounted in a cartridge shell by a shock mount.

Abstract: Special fields for error recovery are provided in data set information tables of data sets written with synchronized transactions. If a transaction only partially fills a data set, that data set is rewritten in a succeeding data set, appending the next transaction. A moving access point in the table identifies the appended transaction, allowing the rewritten transaction to be skipped during read recovery. The table provides recovery trails by providing a thread to tie the data sets together, the status of the data set, and pointers, such as identifying the wrap of the immediately succeeding data set.

Abstract: Synchronized data is written to magnetic tape while reducing the number of backhitches. A controller detects a pattern of synchronizing events for received data records to be written to tape; writes each transaction of data records to the magnetic tape; accumulates the synchronized transactions in a buffer; and subsequently recursively writes the accumulated transactions of data records from the buffer to the magnetic tape in a sequence. A single backhitch may be employed to place the recursively written accumulated data records following the preceding data, maximizing performance and capacity.

Abstract: A sequential buffer for a magnetic tape data storage system comprises a plurality of segments. A buffer management system buffers data in the sequential buffer, conducting a data transfer process. Subsequently, some of the buffered data is maintained in some, but less than all, the segments of the buffer. Additionally, the maintained buffered data is indicated as VALID data. Thus, a subsequent process may be conducted directly using the data maintained in the buffer, and avoids moving the tape to reread the data.

Abstract: Directories are provided for data recorded on a magnetic tape in the form of files having data demarcation signals, such as filemarks. Data storage logic arranges a map of the tape in fixed regions; establishes a window at each intersection between fixed regions, the window extending into at least one of the regions; determines whether at least one data demarcation signal is located in a window; if so, selects and identifies the properties and location of one of the data demarcation signals as within the window. If no data demarcation signal is present, the directory indicates an absence of data demarcation signals within the window.

Abstract: A data storage drive arranged as a plurality of logical accessors accesses data on a removable random access medium. Upon a write access for a data segment by a logical accessor, a control locks a context comprising at least one data segment of a partition to the logical accessor. The control concurrently allows read access to the data of the removable random access medium, except the locked context, and allows write access, except to the locked partition, by other logical accessors.

Abstract: Provided are a method, system, and program for encoding data onto a storage medium. Host data is received and a plurality of device blocks are generated to include the host data. A directory is generated including entries for physical locations on the storage medium, wherein each entry identifies one device block at the physical location corresponding to the entry, and wherein the directory is used to access data on the storage medium. The directory entries are encoded in the device blocks written to the storage medium.

Abstract: Provided are a method, system and article of manufacture for writing on a storage media. Data is received from a host. A determination is made whether the received data can potentially form a trailer record on the storage media. If the received data does not potentially form the trailer record, then the received data is written to the storage media.

Abstract: Directories are provided for data recorded on a magnetic tape in the form of files having data demarcation signals, such as filemarks. Data storage logic arranges a map of the tape in fixed regions; establishes a window at each intersection between fixed regions, the window extending into at least one of the regions; determines whether at least one data demarcation signal is located in a window; if so, selects and identifies the properties and location of one of the data demarcation signals as within the window. If no data demarcation signal is present, the directory indicates an absence of data demarcation signals within the window.

Abstract: Structures are provided for mapping data of any of various formats, and for storing data of a linear sequential format, on a random access medium, e.g., having equal sized, sequentially numbered logical sectors. A third level construct comprises regions for data, identifies the region in terms specific to the format and to the sectors. A second level construct comprises a global device block map having an element for each region, identifying the format and bounds of the region in terms of the sectors and specific format, and associates related regions into partitions. A first level construct comprises a format identifier having a pointer indicating location and size of the second level construct in terms of the sectors. For data of variable length sequential device blocks, each device block has a header with multiple backwards references to close and distant previous device blocks.

Abstract: Synchronized data is written to magnetic tape while reducing the number of backhitches. A controller detects a pattern of synchronizing events for received data records to be written to tape; writes each transaction of data records to the magnetic tape; accumulates the synchronized transactions in a buffer; and subsequently recursively writes the accumulated transactions of data records from the buffer to the magnetic tape in a sequence. A single backhitch may be employed to place the recursively written accumulated data records following the preceding data, maximizing performance and capacity.

Abstract: Special fields for error recovery are provided in data set information tables of data sets written with synchronized transactions. If a transaction only partially fills a data set, that data set is rewritten in a succeeding data set, appending the next transaction. A moving access point in the table identifies the appended transaction, allowing the rewritten transaction to be skipped during read recovery. The table provides recovery trails by providing a thread to tie the data sets together, the status of the data set, and pointers, such as identifying the wrap of the immediately succeeding data set.

Abstract: A data storage drive arranged as a plurality of logical accessors accesses data on a removable random access medium. Upon a write access for a data segment by a logical accessor, a control locks a context comprising at least one data segment of a partition to the logical accessor. The control concurrently allows read access to the data of the removable random access medium, except the locked context, and allows write access, except to the locked partition, by other logical accessors.

Abstract: Structures are provided for mapping data of any of various formats, and for storing data of a linear sequential format, on a random access medium, e.g., having equal sized, sequentially numbered logical sectors. A third level construct comprises regions for data, identifies the region in terms specific to the format and to the sectors. A second level construct comprises a global device block map having an element for each region, identifying the format and bounds of the region in terms of the sectors and specific format, and associates related regions into partitions. A first level construct comprises a format identifier having a pointer indicating location and size of the second level construct in terms of the sectors. For data of variable length sequential device blocks, each device block has a header with multiple backwards references to close and distant previous device blocks.

Abstract: A data storage cartridge having an data storage device, such as an encased magnetic disk drive assembly, is, in one embodiment, of generally an exterior dimensional form factor of a tape cartridge having a leader block with a hole therethrough for engagement by a threading pin. To distinguish the cartridge from a tape cartridge, the cartridge shell comprises a blocking portion at the location of the leader block hole. A transfer station both identifies the cartridge and indicates the presence of the cartridge at an end of travel in a cartridge receiver, employing an optical source and an opposed sensor directed toward the leader block hole when a cartridge is at the end of travel. In another embodiment, an encased magnetic disk drive assembly is supported and mounted in a cartridge shell by a shock mount.

Abstract: Storage shelves of a mass data storage library are organized into a plurality of subsets for the purpose of conducting an inventory of media stored in the shelves. In response to an inventory command, the inventory is conducted in a predetermined order by subset. Upon completion of the inventory of each subset, the completion is posted in a list. A command input detects newly issued commands (subsequent to the inventory command), and places them in a queue. After completion of the inventory of a subset, and upon detecting a command for a non-inventory process (such as a media move), the inventory is interrupted and stopped. The move is conducted, and, upon completion of the move, the inventory is resumed. If a newly issued command is an inventory command, the inventory command is incorporated into the inventory process.