I/O-Devices
Question 1 |
Which one of the following facilitates transfer of bulk data from hard disk to main memory with the highest throughput?
DMA based I/O transfer | |
Interrupt driven I/O transfer | |
Polling based I/O transfer | |
Programmed I/O transfer |
Question 1 Explanation:
Explanation: Both the methods of programmed I/O and Interrupt-driven I/O require the active intervention of the processor to transfer data between memory and the I/O module, and any data transfer must transverse a path through the processor.
DMA or direct memory access allows the peripherals to directly communicate with each other using the memory buses, removing the intervention of the CPU. Hence it is the fast mode of IO transfer compared to all other methods. In polling, the processor wastes countless processor cycles by repeatedly checking each IO device if it needs attention.
DMA or direct memory access allows the peripherals to directly communicate with each other using the memory buses, removing the intervention of the CPU. Hence it is the fast mode of IO transfer compared to all other methods. In polling, the processor wastes countless processor cycles by repeatedly checking each IO device if it needs attention.
Question 2 |
Consider the following statements:
Arithmetic Logic Unit(ALU)
1. Performs arithmetic operations
2. performs comparisons
3. Communicates with I/O devices
4. Keeps watch on the system
Which of these statements are correct?
1 only | |
1 and 2 only
| |
1 and 4
| |
2 and 3
|
Question 2 Explanation:
An arithmetic logic unit (ALU) is a digital circuit used to perform arithmetic and logic operations. It represents the fundamental building block of the central processing unit (CPU) of a computer. Modern CPUs contain very powerful and complex ALUs.
There are 2 questions to complete.