System for accessing distributed memory by breaking each accepted access

Abstract

A distributed memory I/O interface 10 is provided which allows a plurality of standard peripheral bus I/O controllers 101 to perform multiple transfer operations simultaneously and independently within a networked, distributed memory system 102. The interface 10 includes a peripheral interface 11 to the I/O controllers 101, a memory interface 12 to the distributed memory system 102, a system interface 13 to the processors of the distributed memory system 102, a caching circular buffer RAM 12, and an internal bus 105. The operations of the interface 10 are controlled by logical channels. Each logical channel comprises a channel context, which includes a set of parameters stored in buffer RAM 12 that specify among other things logical address space, a physical memory map, a RAM buffer segment, and a set of allowed transactions for use during channel operations. Data is staged through RAM segments which act as circular buffer caches within the channel's logical address space for sequential transfers, and as doubly-mapped shared memory for random access. The use of an intermediate logically contiguous address space and a caching circular buffer, and the methods by which the parameters in the logical channel context are referenced and modified by the components of the interface 10 allows for multiple I/O transfer operations to be active simultaneously and executed independently.