Which among the following is incorrect about DMA?a)The controller performs I/O operations.b)First register in interface stores address.c)The controller gives special access to main memory.d)DMA interface carries status in second register.Correct answer is option 'D'. Can you explain this answer?

Question

Answer

DMA controller allows data transfer directly between I/O device and Memory, with less involvement of processor. The DMA controller acts as a Processor which is controlled by CPU. DMA controller performs the requested I/O operation and sends interrupt to processor on completion. DMA interface stores address in first register, word count in second register and status and control flags in third register.

Hence, the correct option is (D).

Answer

Incorrect Statement about DMA:

The incorrect statement about DMA is option 'D': DMA interface carries status in the second register.

Explanation:

DMA (Direct Memory Access) is a technique in computer systems that allows data to be transferred between peripheral devices and main memory without the need for CPU intervention. DMA controllers are responsible for managing these data transfers.

Let's analyze each option to understand why option 'D' is incorrect.

a) The controller performs I/O operations:
- This statement is correct. The DMA controller is responsible for managing data transfers between peripheral devices and main memory, effectively performing I/O operations.

b) First register in the interface stores address:
- This statement is correct. The DMA controller uses registers to store the memory addresses of the source and destination locations for data transfer. The first register in the interface is typically used to store the address of the source or destination.

c) The controller gives special access to main memory:
- This statement is correct. DMA controllers have direct access to the main memory and can transfer data to or from it without CPU intervention. This allows for faster data transfer rates and efficient utilization of CPU resources.

d) DMA interface carries status in the second register:
- This statement is incorrect. The DMA interface does not carry the status in the second register. The status of DMA operations is typically stored in a separate status register or a set of status bits within the DMA controller. These status bits indicate the progress, completion, or any error conditions during the data transfer.

Conclusion:

The incorrect statement about DMA is option 'D' because DMA interface does not carry the status in the second register. The status of DMA operations is usually stored in a separate status register or status bits within the DMA controller.

Similar Computer Science Engineering (CSE) Doubts

A queue is implemented using an array such that ENQUEUE and DEQUEUE operations are performed efficiently. Which one of the following statements is CORRECT (n refers to the number of items in the queu e)?

A queue is implemented using an array such that ENQUEUE and DEQUEUE operations are performed efficiently. Which one of the following statements is CORRECT ( nrefers to the number of items in the queu e)?

Top Courses for Computer Science Engineering (CSE)View all

GATE Computer Science Engineering(CSE) 2025 Mock Test Series

Question Bank for GATE Computer Science Engineering

General Aptitude for GATE

Computer Networks

Programming and Data Structures

Top Courses for Computer Science Engineering (CSE)

Top Courses for Computer Science Engineering (CSE)

Suggested Free Tests

Related Content

Mock Test Series

Subject-wise Courses

Subject-wise Courses

Other Engg Branches

Company