Abstract: A shared memory provides data access to a plurality of agents (e.g., processor, cells of processors, I/O controllers, etc.) and includes a memory and a memory controller. The memory controller selectively provides memory access to the agents in both coherent and read current modes of operation. In the coherent mode, the memory controller ensures that the data stored in system memory is accurately and precisely mirrored in all subservient copies of that data as might typically be stored in agent cache memories. Using, for example, a MESI type protocol, the memory controller limits access to memory so that only an “owner” or a particular portion or line of memory has write access and that, during the extension of these write privileges, no other agent has a valid copy of the data subject to being updated. Thus, the memory controller implements a first set of rule in the coherent mode of operation to insure that all copies of data stored by the agents are coherent with data stored in the memory.

Abstract: A snapshot mechanism that includes an apparatus and method for tracking DMA read requests for cacheable data that can be altered before the data is returned to a requesting I/O device is herein disclosed. Attributes that uniquely identify the original I/O device and DMA read request are stored in a cache tag unit. A read lock is set when a request is made to obtain the requested data when it is not resident in a local cache. When the cache line containing the requested data is snooped out and the read lock is set, then the cache line is set in a snapshot state. The snapshot state assures that only the original I/O device receives the read data when it has been altered subsequent to the time the original DMA read request was made. Once the data is returned to the original I/O device, the cache line is invalidated in order to prevent another I/O device from reading the stale data. Prefetched data is marked as such and cannot be marked as snapshot data.

Abstract: The present invention concerns a putter used in the game of golf. Specifically, the putter of the present invention is designed so that the sweet spot on the clubhead is generally aligned with the golfer's hand(s) when positioned at the top of the shaft, for a short shafted putter, and the center of the shaft, for a long shafted putter. The basic design requires a shaft which is affixed toward the toe end of the clubhead. The overall configuration of the golf putter of the present invention promotes a golfswing in which the sweet spot and the golfer's hand(s) travel together along the target line, thereby creating a straight putting stroke.