Direct Memory Access(DMA) Structure 直接内存访问DMA结构 Used for high-speed l/o devices able to transmit information at close to memory speeds 用于高速MO设备能够以接近存储器的速率传送信息 Device controller transfers blocks of data from buffer storage directly to main memory without CPU intervention. 无须cPU的介入,设备控制器直接把数据块从缓冲区存储传送到 主存 Only one interrupt is generated per block, rather than the one interrupt per byte 每数据块只要一个中断,而不是每个字节一个中断 Applied Operating System Concepts 2.10Applied Operating System Concepts 2.10 Direct Memory Access (DMA) Structure 直接内存访问(DMA)结构 • Used for high-speed I/O devices able to transmit information at close to memory speeds. 用于高速I/O设备能够以接近存储器的速率传送信息 • Device controller transfers blocks of data from buffer storage directly to main memory without CPU intervention. 无须CPU的介入，设备控制器直接把数据块从缓冲区存储传送到 主存 • Only one interrupt is generated per block, rather than the one interrupt per byte. 每数据块只要一个中断，而不是每个字节一个中断