What Is the Role of a “DAG File” in Memory-Hard Mining Algorithms?

DAG stands for Directed Acyclic Graph. In memory-hard algorithms like Ethash, the DAG file is a large, unique dataset that must be generated and loaded into the miner's GPU memory before mining can begin.

This file is what makes the algorithm memory-hard. It changes periodically (epochs), requiring the miner to reload it, which is a key part of the ASIC resistance mechanism.