Consider the disk drive with the following specifications $$16$$ surfaces, $$512$$ tracks/surface, $$512$$ sectors/track, $$1$$ $$KB/sector$$, rotation speed $$3000$$ $$rpm.$$ 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 interface reads a $$4$$ byte word from the memory in each $$DMA$$ cycle. Memory cycle time is $$40$$ $$nsec$$. The maximum percentage of time that the $$CPU$$ gets blocked during $$DMA$$ operation is

A device with data transfer rate $$10$$ $$KB/sec$$ is connected to a $$CPU.$$ Data is transferred byte-wise. Let the interrupt overhead be $$4$$ $$\mu \sec $$. The byte transfer time between the device interface register and $$CPU$$ or memory is negligible. What is the minimum performance gain of operating the device under interrupt mode over operating it under program controlIed mode?

Normally user programs are prevented from handling $${\rm I}/O$$ directly by $${\rm I}/O$$ instructions in them. For $$CPUs$$ having explicit $${\rm I}/O$$ instructions, such $${\rm I}/O$$ protection is ensured by having the $${\rm I}/O$$ instructions privileged. In a $$CPU$$ with memory mapped $${\rm I}/O$$, there is no explicit $${\rm I}/O$$ instruction. Which one of the following is true for a $$CPU$$ with memory mapped $${\rm I}/O$$ ?

The data given below. Solve the problems and choose the correct answer.

The normalized representation for the above format is specified as follows. The mantissa has an implicit preceding the binary (radix) point. Assume that only $$0's$$ are padded in while shifting a field. The normalized representation of the above $$\left( {0.239 \times {2^{13}}} \right)$$ is