Which of the following interfaces perform the transfer of data between the memory and the I/O peripheral without involving the CPU?
Explanation
The correct option is A) DMA.
Detailed Step-by-Step Explanation
1. What is DMA?
DMA stands for Direct Memory Access. It is a prominent feature of modern computer architectures that allows certain hardware subsystems to access main system memory (RAM) independently of the Central Processing Unit (CPU).
2. The Core Working Mechanism
In conventional programmed I/O or interrupt-driven I/O data transfer methods, the CPU must act as an intermediary for every read and write cycle. The process can be modeled sequentially as:
I/O Peripheral⟶CPU⟶Memory
This consumes significant CPU cycles and slows down high-speed data transfers.
To overcome this limitation, the DMA controller takes control of the system buses (Address, Data, and Control buses) from the CPU. Once authorization is granted, the path is simplified to a direct link:
I/O Peripheral⟷Memory
Mathematically, during this high-speed direct transfer phase, the time overhead contributed by the processor reduces to zero:
CPU Involvement=0%
