The journey of an I/O request in the block layer

The following table provides a concise overview of the structures that were covered in the previous section:

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Structure	Representation of	Description
gendisk	Physical disk	This is used to represent the physical device as a whole and contains information such as the disk’s capacity and geometry
block_device	Block device	This represents a specific instance of a device and contains information such as the major and minor numbers, partitions, and the queue to handle I/O requests
buffer_head	Block of data in memory	This is used to track the data that is read from or written to a block device in memory