Memory consistency research, as one of the core issues of computer architecture, mainly focused on the CPU access memory，while the consistency issues of DMA operations is seldom studied. According to the idea of integrating the architecture design of I/O and memory, the paper defines the concept of general program included I/O operations, aimed at the consistency issues of DSM (distributed shared memory) systems with global DMA operations. The paper studies the general memory consistency model, and builds the general scope consistency model. Based on the general scope memory consistency model, the Cache-Memory-I/O consistency protocol and its implement technology are studied. All this may help the global shared parallel I/O system design for DSM system.