Abstract: A remote resource management system for managing resources in a symmetrical multiprocessing environment having a plurality of clusters of symmetric multiprocessors each of which provides interfaces between cluster nodes of the symmetric multiprocessor system with a local interface and an interface controller. One or more remote storage controllers each has a local interface controller and a local-to-remote data bus. A remote fetch controller is responsible for processing data accesses across the clusters and a remote store controller is responsible for processing data accesses across the clusters. These controllers work in conjunction to provide a deadlock avoidance system for preventing hangs.

Abstract: A remote resource management system for managing resources in a symmetrical multiprocessing environment having a plurality of clusters of symmetric multiprocessors each of which provides interfaces between cluster nodes of the symmetric multiprocessor system with a local interface and an interface controller. One or more remote storage controllers each has a local interface controller and a local-to-remote data bus. A remote fetch controller is responsible for processing data accesses in accordance with the methods described.

Abstract: Disclosed is an apparatus and means for searching a cache directory with full ECC support without the latency of the ECC logic on every directory search. The apparatus allows for bypassing the ECC logic in an attempt to search the directory. When a correctable error occurs which causes the search results to differ, a retry will occur with the corrected results used on the subsequent pass. This allows for the RAS characteristics of full ECC but the delay of the ECC path will only be experienced when a correctable error occurs, thus reducing average latency of the directory pipeline significantly. Disclosed is also a means for notifying the requester of a retry event and the ability to retry the search in the event that the directory is allowed to change between passes.

Abstract: A method for resolving address contention and prioritization of access to resources within a shared memory system includes dynamically creating ordered lists of requests for each contested resource. A new request is added to the lists only after a conflict is recognized. Since the resource conflict does not always exist, there is no impact to a request for an uncontested resources.

Abstract: A remote resource management system for managing resources in a symmetrical multiprocessing environment having a plurality of clusters of symmetric multiprocessors each of which provides interfaces between cluster nodes of the symmetric multiprocessor system with a local interface and an interface controller. One or more remote storage controllers each has a local interface controller and a local-to-remote data bus. The system is provided with a remote resource manager for managing the interface between a plurality of clusters of symmetric multiprocessors each of which clusters has a plurality of processors, a shared cache memory, a plurality of I/O adapters and a main memory accessible from the cluster. A remote fetch controller is responsible for processing data accesses across the clusters and a remote store controller is responsible for processing data accesses across the clusters.

Abstract: A remote resource management system for managing resources in a symmetrical multiprocessing environment having a plurality of clusters of symmetric multiprocessors each of which provides interfaces between cluster nodes of the symmetric multiprocessor system with a local interface and an interface controller. One or more remote storage controllers each has a local interface controller and a local-to-remote data bus. The system is provided with a remote resource manager for managing the interface between a plurality of clusters of symmetric multiprocessors each of which clusters has a plurality of processors, a shared cache memory, a plurality of I/O adapters and a main memory accessible from the cluster. A remote fetch controller is responsible for processing data accesses across the clusters and a remote store controller is responsible for processing data accesses across the clusters.

Abstract: A high speed remote storage controller system for a computer system has cluster nodes of symmetric multiprocessors. A plurality of clusters of symmetric multiprocessors each of has a plurality of processors, a shared cache memory, a plurality of I/O adapters and a main memory accessible from the cluster. Each cluster has an interface for passing data between cluster nodes of the symmetric multiprocessor system. Each cluster has a local interface and interface controller. The system provides one or more remote storage controllers each having a local interface controller and a local-to-remote data bus. A remote resource manager manages the interface between clusters of symmetric multiprocessors. The remote store controller is responsible for processing data accesses across a plurality of clusters and processes data storage operations involving shared memory.

Abstract: A central processor uses virtual addresses to access data via cache logic including a DAT and ART, and the cache logic accesses data in the hierarchical storage subsystem using absolute addresses to access data, a part of the first level of the cache memory includes a translator for virtual or real addresses to absolute addresses. When requests are sent for a data fetch and the requested data are not resident in the first level of cache the request for data is delayed and may be forwarded to a lower level of said hierarchical memory, and a delayed request may result in cancellation of any process during a delayed request that has the ability to send back an exception. A delayed request may be rescinded if the central processor has reached an interruptible stage in its pipeline logic at which point, a false exception is forced clearing all I the wait states while the central processor ignores the false exception.

Abstract: A computer system having central processors (CPs), an associated L2 cache, and processor memory arrays (PMAs), is provided with store logic and and fetch logic used to detect and correct data errors and to write the resulting data the associated cache. The store logic and and fetch logic blocks UEs from the cache for CP stores, for PMA (mainstore) fetches/loads, and for cache-to-cache loads, and with uncorrectable error recovery cache fetch and store logic injects `Special UEs` into the cache when loads cannot be blocked and abends CP jobs for UEs during CP stores, for UEs from PMA, for UEs from remote cache, and for UEs from local cache.

Abstract: Disclosed is a hardware mechanism for detecting and avoiding potential deadlocks among requestors in a multiprocessor system, consisting of a plurality of CP's and I/O adapters connected to one or more shared storage controllers (SC's). Requests to each storage controller originate from external sources such as the CP's, the I/O adapters, and the other SC, as well as from internal sources, such as the hardware facilities used to process fetches and stores between the SC and main memory. All requests must be granted priority before beginning to execute, using a ranked priority order scheme. Specific sequences of requests may cause deadlocks, either due to high-priority requests using priority cycles and locking out low-priority requests, or as a result of requests of any priority level busying resources needed for the completion of other requests.

Abstract: A pipelined multiprocessor system for ESA/390 operations which executes a simple instruction set in a hardware controlled execution unit and executes a complex instruction set in a milli-mode architected state with a millicode sequence of simple instructions in the hardware controlled execution unit, comprising a plurality of CPU processors each of which is part of said multiprocessing system and capable of generating and responding to a quiesce request, and controls for system operations which allow the CPUs in the ESA/390 system to process the local buffer update portion of IPTE and SSKE operations without waiting for all other processors to reach an interruptible point, and then to continue program execution with minor temporary restrictions on operations until the IPTE or SSKE operation is globally completed. In addition, Licensed Internal Code (LIC) sequences are defined which allow these IPTE and SSKE operations to co-exist with other operations which require conventional system quiescing (i.e.

Abstract: A pipelined multiprocessor system for ESA/390 operations which executes a simple instruction set in a hardware controlled execution unit and executes a complex instruction set in a milli-mode architected state with a millicode sequence of simple instructions in the hardware controlled execution unit, comprising a plurality of CPU processors each of which is part of said multiprocessing system and capable of generating and responding to a quiesce request, and controls for system operations which allow the CPUs in the ESA/390 system to process the local buffer update portion of IPTE and SSKE operations without waiting for all other processors to reach an interruptible point, and then to continue program execution with minor temporary restrictions on operations until the IPTE or SSKE operation is globally completed. In addition, Licensed Internal Code (LIC) sequences are defined which allow these IPTE and SSKE operations to co-exist with other operations which require conventional system quiescing (i.e.

Abstract: A method using a global hang pulse logic mechanism detects and resolves deadlocks among requesters to the storage controller of a symmetric multiprocessor system in which multiple central processors and I/O adapters are connected to one or more shared storage controllers. Deadlocks may occur in such a system due to specific sequences of requests, either because high priority requests use priority cycles and lock out low priority requests, or because requests of any priority level make resources needed for the completion of other requests too busy. The mechanism logic monitors the length of time a request has been valid in the storage controller without completing, by checking the request register valid bits, and by utilizing a timed pulse which is a subset of the pulse used to detect hangs within the storage controller.

Abstract: A remote resource management system for managing resources in a symmetrical multiprocessing comprising a plurality of clusters of symmetric multiprocessors having interfaces between cluster nodes of the symmetric multiprocessor system. Each cluster of the system has a local interface and interface controller. There are one or more remote storage controllers each having its local interface controller, and a local-to-remote data bus. The remote resource manager manages the interface between two clusters of symmetric multiprocessors each of which clusters has a plurality of processors, a shared cache memory, a plurality of I/O adapters and a main memory accessible from the cluster. This remote resource manager manages resources with a remote storage controller to distribute work to a remote controller acting as an agent to perform a desired operation without requiring knowledge of a requester who initiated the work request.

Abstract: A hierarchical cache architecture that reduces traffic on a main memory bus while overcoming the disadvantages of prior systems. The architecture includes a plurality of level one caches that are of the store through type, each level one cache is associated with a processor and may be incorporated into the processor. Subsets (or "clusters") of processors, along with their associated level one caches, are formed and a level two cache is provided for each cluster. Each processor-level one cache pair within a cluster is coupled to the cluster's level two cache through a dedicated bus. By configuring the processors and caches in this manner, not only is the speed advantage normally associated with the use of cache memory realized, but the number of memory bus accesses is reduced without the disadvantages associated with the use of store in type caches at level one and without the disadvantages associated with the use of a shared cache bus.

Abstract: A resource arbitration system is provided implementing a modified round robin priority selection logic including resource checking and lockout avoidance that updates the round robin priority token only when (1) the process request is granted and (2) there are no prior processes with resource conflicts. The resource arbitration system thereby allows each process request to get into the queue with high priority once the requested resource is freed.

Abstract: Insures data integrity in process ownership indications by providing an ownership interlock on the data units in a pipeline to a store-in type of cache. An ownership interlock prevents any processor ownership change to occur (i.e. exclusive or readonly ownership) for a cache data unit until all outstanding stores have been made in the cache data unit, after which the ownership may be changed. An ownership change may be signalled by a cross-invalidate (XI) signal to a processor. Outstanding stores are received by the pipeline after the stores are completed by a processor, and the outstanding stores output from the pipeline into a store-in cache. A continuous flow of stores is enabled into and out of the pipeline to expedite a change of ownership requested of a data unit in the cache. The continuous flow avoids having to stop a processor from putting stores into the pipeline and avoids forcing all outstanding stores out of the pipeline into the cache before indicating a change of processor ownership.