Abstract: An opaque memory region for a bridge of an I/O adapter. The opaque memory region is inaccessible to memory transactions which traverse the bridge either from a primary bus to secondary bus or secondary bus to primary bus. As a result, memory transactions which target the opaque memory region are ignored by the bridge, allowing for the same address to exist on both sides of the bridge with different data stored in each. The implementation of the opaque memory region provides a means to complete memory transactions within I/O adapter subsystem memory, hence, relieving host computer system memory resources. In addition, a number of I/O adapters can be used in a host computer system where the host and all the I/O devices use some of the same memory addresses.

Abstract: Dynamic routing of data to multiple processor complexes. PCI address space is subdivided among a plurality of processor complexes. Translation table entries at each processor complex determine which processor complex is to receive a DMA transfer, thereby enabling routing of DMA data to one I/O hub node while accessing translation table entries at another I/O hub node. Further, interrupt requests may be dynamically routed to multiple processor complexes.

Abstract: To prevent data performance impacts when dealing with target devices that can only transfer data for a limited number of bytes before disconnecting, the invention implements a short term data cache on the bridge. Using this feature, the bridge will cache additional data beyond a predetermined quantity of data following a disconnect with the requesting device. As such, the bridge may continue to prefetch additional data up to an amount specified by a prefetch read byte count and return the additional data should the requesting device request additional data resuming at the point of disconnect. However, the bridge will discard the additional data when at least one of the following occurs: a) the requesting device disconnects data transfer, and b) a further READ request that resumes at the point of disconnect is not received within a predetermined time.

Abstract: Private devices are implemented on the secondary interface of PCI bridge by re-routing the activation of device select signals (IDSEL) during the address phase of a Type 0 configuration operation on the secondary bus in response to a Type 1 configuration operation on its primary bus. Under control of a mask register and device select reroute circuit, if a configuration command on the primary interface attempts to activate the IDSEL line associated with one of the private, or reroute, devices on the secondary interface, a different IDSEL is activated to select a monitoring device on the secondary interface.

Abstract: An opaque memory region for a bridge of an I/O adapter. The opaque memory region is inaccessible to memory transactions which traverse the bridge either from a primary bus to secondary bus or secondary bus to primary bus. As a result, memory transactions which target the opaque memory region are ignored by the bridge, allowing for the same address to exist on both sides of the bridge with different data stored in each. The implementation of the opaque memory region provides a means to complete memory transactions within I/O adapter subsystem memory, hence, relieving host computer system memory resources. In addition, a number of I/O adapters can be used in a host computer system where the host and all the I/O devices use some of the same memory addresses.

Abstract: The parallelism of a multi-pipelined digital computer is enhanced by detection of branch instructions from the execution pipelines and concurrent processing of up to two of the detected instructions in parallel with the operations of the execution pipelines. Certain branch instructions, when detected, are removed altogether from the pipeline, but still processed. The processing is synchronized with the execution pipeline to, first, predict an outcome for detected branch instructions, second, test the conditions for branch instructions at their proper place in the execution sequence to determine whether the predicted outcome was correct, and third, fetch a corrected target instruction if the prediction proves wrong.

Abstract: A steering wheel assembly for vehicles which incorporates an energy absorbing coupling which mounts the steering wheel for tilting movement with respect to a column to an optimum impact position when the wheel receives inertia load and which provides for subsequent energy management by deformation of a plurality of metallic legs which collapse at controlled rates.