Question

Match List-I with List-II and select the correct answer using the code given below the lists:

List-I		List-II
A.	DMA I / O	1.	High-speed RAM
B.	Cache	2.	Disk
C.	Interrupt I / O	3.	Printer
D.	Condition code registers	4.	ALU

1. A-4, B-1, C-3, D-2
2. A-2, B-1, C-3, D-4
3. A-4, B-3, C-1, D-2
4. A-2, B-3, C-1, D-4

Answer 1

Correct Answer - Option 2 : A-2, B-1, C-3, D-4

Direct Memory Access (DMA): The data transfer between a fast storage media such as magnetic disk and memory unit is limited by the speed of the CPU. Thus we can allow the peripherals to directly communicate with each other using the memory buses, removing the intervention of the CPU. This type of data transfer technique is known as DMA or direct memory access.

Interrupt-initiated I/O:  By using an interrupt-driven method and special commands to inform the interface to issue an interrupt request signal whenever data is available from any device. In the meantime, the CPU can proceed with any other program execution. The interface meanwhile keeps monitoring the device. Whenever it is determined that the device is ready for data transfer it initiates an interrupt request signal to the computer. In the case of printers, we use the interrupt-driven I/O method.

Condition code register: The CCR contains five flag bits(carry, overflow, zero, negate, extend), which are set by the ALU to hold information about the result of an arithmetic or logical operation instruction that has just been executed.

Cache memory: it is an extremely fast memory. It holds frequently requested data and instructions so that they are immediately available to the CPU when needed.