Abstract: A deadlock-prevention system includes a resource-access key passed from a parent process to a spawned process that includes the parent processes' level of access to a system resource. Optionally, the resource-access key includes a shared-access request based on the expectation by the parent process that the child process will need shared-access to a system resource. The resource-access key is presented by the child process to a resource-allocation algorithm. The resource-allocation algorithm identifies the resource-access key, allows the child process to bypass a resource-allocation queue, and grants shared access to the resource to the child process, preventing deadlock.

Abstract: Data management systems, such as used in disk control units, employ memory entry lists to help keep track of user data. Improved performance of entry list maintenance is provided by the present invention. Much of the protocol employed to conduct such maintenance is preferably performed by hardware-based logic, thereby freeing other system resources to execute other processes. New entries to the memory list are only allowed at predetermined addresses and entries are updated by writing a predetermined data pattern to a previously allocated address. Optionally, improved error detection, such as a longitudinal redundancy check, may also be performed in an efficient manner during entry list maintenance to assure the integrity of the list.

Abstract: Provided are a method, system and program for updating data shared among systems. A first and second systems maintain a first and second copies, respectively, of shared data stored in a storage device. The first system obtains a first lock to the shared data, wherein the first lock applies to the first system accessing the shared data. The first system sends to the second system a first message requesting a second lock to the shared data, wherein the second lock applies to the second system accessing the shared data; The second system obtains the second lock to the shared data for the first system in response to the first message sends to the first system a second message indicating the second lock to the shared data was granted.

Abstract: Provided are a method, system, and program for managing write processes in which a list of destination location identifiers for pending write operations is maintained in an array having an array pointer which identifies the next available entry of the array. In one embodiment, the array includes a stack of variable size. Adding a destination location identifier of a pending write operation increases the size of the stack. Removing a destination location identifier of a completed write operation reduces the size of the stack. A stack index may be incremented as write operation destination location identifiers are added and may be decremented as write operation destination location identifiers are removed from the stack.

Abstract: A method, system, and article of manufacture for recovering from a track format error detected by a host computer associated with a storage controller associated with a storage disk array. The recovery method begins with saving a copy of the track format information associated with the data track that triggered the track format error in a predetermined location. Next, the track format information associated with the data track that caused the error is invalidated and the subject data is restaged. Subsequently, the restaged data is compared to the saved copy of the track format information to determine if the track format error exists with respect to the restaged data. If the track format error is detected with respect to the restaged data, the method further consists of reconstructing the data, preferably by performing a reconstruct read recovery.

Abstract: A method to initialize information disposed in an information storage and retrieval system comprising a data cache and one or more information storage media comprising a plurality of addresses. The method receives an initialization command, where that initialization command comprises a range of addresses and, optionally, an initialization pattern, where the plurality of addresses includes the range of addresses. The method forms and saves state information, where that state information includes the initialization pattern, and generates and saves a plurality of indicators, where that plurality of indicators includes an indicator for each track comprising the range of addresses. The method sets each of those indicators to a first value thereby indicating special handling, and provides an ending status signal, such that the receiving step, forming step, generating step, setting step, and providing step are performed substantially synchronously.