Consider a disk drive with following specifications: 16 surfaces, 512 tracks/surface, 512 sectors/sector, 1KB/sector, rot. speed 3000rpm. The disk is operated in cycle stealing mode whereby whenever one byte word is ready it is sent to memory; similarly for writing the disk surface reads a 4 byte word from the memory in each dma cycle. Memory cycle time is 40ns. The max. percentage of time that cpu gets blocked during dma operation:
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