自从1946年美国宾夕法尼亚大学研制出世界上第一台电子数字计算机ENIAC以来,I/O(输入输出)瓶颈问题时间刻困绕着人们。一方面,由于主存储器容量小且价格昂贵,虽然采用了交换、覆盖等技术,在硬件上采用了通道并行操作、缓冲池和DMA技术,但还是需要大容量的外部存储器;另一方面,CPU要与外界通讯,所以I/O设备是计算机系统的重要组成部分。 Since 1946, the University of Pennsylvania developed the world’s first electronic digital computer ENIAC, I / O (bottleneck) of I / O time-bound problems around the people. On the one hand, due to the small main memory capacity and the high cost, although the use of exchange, coverage and other technologies, the hardware used in the channel parallel operation, buffer pool and DMA technology, but still need large-capacity external memory; the other hand, the CPU To communicate with the outside world, I / O devices are an important part of a computer system.