Abstract: A memory subsystem includes memory devices with space dynamically allocated for improvement of reliability, availability, and serviceability (RAS) in the system. Error checking and correction (ECC) logic detects an error in all or a portion of a memory device. In response to error detection, the system can dynamically perform one or more of: allocate active memory device space for sparing to spare a failed memory segment; write a poison pattern into a failed cacheline to mark it as failed; perform permanent fault detection (PFD) and adjust application of ECC based on PFD detection; or, spare only a portion of a device and leave another portion active, including adjusting ECC based on the spared portion. The error detection can be based on bits of an ECC device, and error correction based on those bits and additional bits stored on the data devices.

Abstract: Examples herein relate to checkpoint replication and copying of updated checkpoint data. For example, a memory controller coupled to a memory can receive a write request with an associated address to write or update checkpoint data and track updates to checkpoint data based on at least two levels of memory region sizes. A first level is associated with a larger memory region size than a memory region size associated with the second level. In some examples, the first level is a cache-line memory region size and the second level is a page memory region size. Updates to the checkpoint data can be tracked at the second level unless an update was previously tracked at the first level. Reduced amounts of updated checkpoint data can be transmitted during a checkpoint replication by using multiple region size trackers.

Abstract: A system can dynamically migrate memory pages from near memory to far memory during runtime. A system basic input output system (BIOS) can program a first memory address space of size P and a second memory address space of size P to a near memory (NM) space of size (N) and a far memory (FM) space of size (M), where P equals N+M. For the first memory address space, the OS can manage the NM space and the FM space as a flat memory space with an address space of size P available. For the second memory address space, the OS can manage the NM space as a NM cache for FM, with an address space of size M available.

Abstract: Examples include techniques to expand system memory via use of available device memory. Circuitry at a device coupled to a host device partitions a portion of memory capacity of a memory configured for use by compute circuitry resident at the device to execute a workload. The partitioned portion of memory capacity is reported to the host device as being available for use as a portion of system memory. An indication from the host device is received if the portion of memory capacity has been identified for use as a first portion of pooled system memory. The circuitry to monitor usage of the memory capacity used by the compute circuitry to execute the workload to decide whether to place a request to the host device to reclaim the memory capacity from the first portion of pooled system memory.

Abstract: Examples herein relate to checkpoint replication and copying of updated checkpoint data. For example, a memory controller coupled to a memory can receive a write request with an associated address to write or update checkpoint data and track updates to checkpoint data based on at least two levels of memory region sizes. A first level is associated with a larger memory region size than a memory region size associated with the second level. In some examples, the first level is a cache-line memory region size and the second level is a page memory region size. Updates to the checkpoint data can be tracked at the second level unless an update was previously tracked at the first level. Reduced amounts of updated checkpoint data can be transmitted during a checkpoint replication by using multiple region size trackers.

Abstract: A method, apparatus, and computer program product diagnosing and resolving faults is disclosed. A disclosed fault management architecture includes a fault manager suitable having diagnostic engines and fault correction agents. The diagnostic engines receive error information and identify associated fault possibilities. The fault possibility information is passed to fault correction agents, which diagnose and resolve the associated faults. The architecture uses logs to track the status of error information, the status of fault management exercises, and the fault status of system resources. Additionally, a soft error rate discriminator can be employed to track and resolve soft (correctible) errors in the system. The architecture is extensible allowing additional diagnostic engines and agents to be plugged in to the architecture without interrupting the normal operational flow of the computer system.

Abstract: A method for managing a fault involves detecting an error, gathering data associated with the error to generate an error event, and categorizing the error event using a hierarchical organization of the error event.

Abstract: A mechanism for replicating and maintaining files in a space-efficient manner is disclosed. In one embodiment, a current file is replicated by associating the data blocks of the current file with both the current file and a new file. The new file and the current files are separate and distinct from each other. Data blocks remain shared until the content of one file is modified. Only the data blocks affected by the modification are duplicated. The two files share the unchanged data blocks, but both files are each associated with additional data blocks that reflect the modification. Reference values are used to track how many files are associated with each data block. In another embodiment, a file descriptor is linked to a filename at the request of a user or application. The present invention avoids needless duplication of the same data blocks among copies of a file.

Abstract: A system for providing extended file attributes is described. Logically, attributes are supported as files within the file system. In this way, the file system is augmented with an orthogonal namespace of file attributes. According, any file (including attribute files) may have an arbitrarily deep attribute tree associated with it. Access to the attribute values is via file descriptors obtained via a special attribute interface. This logical view of “attributes as files” allows the leveraging of existing file system interface functionality to support the construction, deletion, and manipulation of attributes.

Abstract: A mechanism for replicating and maintaining files in a space-efficient manner is disclosed. In one embodiment, a current file is replicated by associating the data blocks of the current file with both the current file and a new file. The new file and the current files are separate and distinct from each other. Data blocks remain shared until the content of one file is modified. Only the data blocks affected by the modification are duplicated. The two files share the unchanged data blocks, but both files are each associated with additional data blocks that reflect the modification. Reference values are used to track how many files are associated with each data block. In another embodiment, a file descriptor is linked to a filename at the request of a user or application. The present invention avoids needless duplication of the same data blocks among copies of a file.

Abstract: A mechanism for replicating and maintaining files in a space-efficient manner is disclosed. In one embodiment, a current file is replicated by associating the data blocks of the current file with both the current file and a new file. The new file and the current files are separate and distinct from each other. Data blocks remain shared until the content of one file is modified. Only the data blocks affected by the modification are duplicated. The two files share the unchanged data blocks, but both files are each associated with additional data blocks that reflect the modification. Reference values are used to track how many files are associated with each data block. In another embodiment, a file descriptor is linked to a filename at the request of a user or application. The present invention avoids needless duplication of the same data blocks among copies of a file.

Abstract: Improved techniques for providing users and application programs with access to data stored in computer systems are disclosed. The improved techniques are particularly well suited for use in computer systems where data can be logically organized in files presented in a file system. A multilevel caching system suitable for storing information relating to files in the file system is provided. The stored information can include file references suitable for locating files in the file system as well as other useful information about the file system. The multilevel caching system provides the ability to implement various caching strategies at different levels and increases the probability of cache hits when seeking to locate files in a file system. Accordingly, relatively expensive read operations to persistent storage devices can be minimized when locating files in the file system.

Abstract: A system for providing extended file attributes is described. Logically, attributes are supported as files within the file system. In this way, the file system is augmented with an orthogonal namespace of file attributes. According, any file (including attribute files) may have an arbitrarily deep attribute tree associated with it. Access to the attribute values is via file descriptors obtained via a special attribute interface. This logical view of “attributes as files” allows the leveraging of existing file system interface functionality to support the construction, deletion, and manipulation of attributes.

Abstract: A bootstrap system for a computer with peripheral devices has a first level boot firmware program and a second level boot program loaded from disk by the first level program. The second level boot program contains a device tree constructed according to IEEE-1275 (Open Firmware) standards, describing currently known peripheral devices and computer resource allocations. The device tree is modifiable during boot operations to incorporate information about additional devices. The second level boot program scans I/O buses for additional devices not included in the current device tree and loads drivers only for the additional devices. The second level boot program further allows a user to enter information into the device tree. The second level boot program is preferably implemented under DOS emulation, and may be developed in a DOS-based code development environment and ported to the computer.