摘要:
Indicating when the cover for a computer chassis has been opened is disclosed. A computer of an embodiment of the invention includes a chassis and a basic input/output system (BIOS), or another type of firmware. The chassis has an openable cover, and circuitry indicating when the openable cover has been opened. The BIOS has a non-volatile memory in which a flag is set when the circuitry indicates that the openable cover has been opened. The computer may further include always-on circuitry, such as time-of-day and real-time clock circuitry, to which the circuitry indicating when the openable cover has been opened is electrically connected. The computer may also include one or more encryption and/or signing modules that encrypt and/or sign data according to one or more keys. The keys are rendered invalid when the cover of the chassis has been opened.
摘要:
A method and apparatus are provided for maintaining data integrity when switching between data protection methods. Data and a first protection type information are received. A second protection type information is generated. After generating the second protection type information, the data is checked using the first protection type information. An error indication is generated when the first protection type information check fails.
摘要:
Utilizing a hardware transactional approach to execute a code section by employing pseudo-transactions, after initially utilizing software locking, is disclosed. A method is disclosed that utilizes a software approach to locking memory to execute a code section relating to memory. The software approach employs a pseudo-transaction to determine whether a hardware approach to transactional memory to execute the threshold would have been successful. Where the hardware approach to transactional memory to execute the code section satisfies a threshold based on success of at least the pseudo-transaction, the method subsequently utilizes the hardware approach to execute the code section. The hardware approach may include starting a transaction inclusive of the code section, conditionally executing the transaction, and, upon successfully completing the transaction, committing execution of the transaction to the memory to which the code section relates.
摘要:
Atomic renaming and moving of data files, while permitting lock-free look-ups to the data files, is disclosed. A temporary record may be created within a hash chain encompassing a record for a data file and corresponding to a location of the data file within a computer file system. The temporary record is linked within the hash chain so that the temporary record points to the same records to which the record for the data file points. The record for the data file is renamed with a new name, and/or moved to a new location within the computer file system, and the temporary record is removed from the hash chain. Before the temporary record is removed, look-ups of the data file resolve to the temporary record, the temporary record causing the look-ups to wait until the record for the data file has been renamed and/or moved and the temporary record removed.
摘要:
A technique for realtime-safe detection of a grace period for deferring the destruction of a shared data element until pre-existing references to the data element have been removed. A per-processor read/write lock is established for each of one or more processors. When reading a shared data element at a processor, the processor's read/write lock is acquired for reading, the shared data element is referenced, and the read/write lock that was acquired for reading is released. When starting a new grace period, all of the read/write locks are acquired for writing, a new grace period is started, and all of the read/write locks are released.
摘要:
A system, method and computer program product for enhancing a real-time operating system (RTOS) with functionality normally associated with a general purpose operating system (GPOS). A hypervisor that is adapted to perform a real-time scheduling function supports concurrent execution of an RTOS and a GPOS on a system of shared hardware resources. The RTOS or its applications can utilize services provided by the GPOS. Such services may include one or more of file system organization, network communication, network management, database management, security, user-interface support and others. To enhance operational robustness and security, the hypervisor can be placed in read-only storage while maintaining the ability to update scheduling mechanisms. A programmable policy manager that is maintained in read-write storage can be used to dictate scheduling policy changes to the hypervisor as required to accommodate current needs.
摘要:
A system, method and computer program product for atomically moving a shared list element from a first list location to a second list location includes inserting a placeholder element at the second list location to signify to readers that a move operation is underway, removing the shared list element from the first list location, re-identifying the list element to reflect its move from the first list location to the second list location, inserting it at the second list location and unlinking the placeholder element. A deferred removal of the placeholder element is performed following a period in which readers can no longer maintain references thereto. A method, system and computer program product are additionally provided for performing a lookup of a target list element that is subject to being atomically moved from a first list to a second list.
摘要:
A method and apparatus for restricting access of an application to computer hardware. The apparatus includes both an authentication module and a validation module. The authentication module is within the trusted firmware layer. The purpose of the authentication module is to verify a cryptographic key presented by an application. The validation module is responsive to the authentication module and limits access of the application to the computer hardware. The authentication modules may be implemented in software through a firmware call, or through a hardware register of the computer.
摘要:
A system and method is provided to support immediate freeing of a designated element from memory. Following a process of designating an element for removal from a data-structure, conditional limitations are used to determine if immediate freeing of the element from memory is available. The conditional limitations include determining that the instruction originates from a uniprocessor computer system. In addition, the conditional limitations include a determination as to whether a call_rcu primitive or synchronize_kernel primitive may be omitted, or whether the computer implemented instruction is operating in an interrupt handler. If the conditional limitations are met, the designated element may be immediately freed from memory.
摘要:
Typical embodiments of the present invention maintain the cache metadata in arrays, and use vector instructions to process the array elements in parallel. The cache metadata comprises virtual tags corresponding to main memory addresses and physical addresses corresponding to cache memory addresses. The virtual tags and physical addresses may be interleaved in a single array in the cache memory. Alternately, virtual tags and physical addresses may be maintained in corresponding separate arrays. A roving pointer may be used to identify the next block to be ejected from the cache memory.