docker images are built in a layered format, with lower layers being read-only and the upper layer available for editing. Creating a new image which shares the same base layers as another image does not copy the layers, but instead follows COW principles and allows the two images to share layers until one is edited.

In computer storage

COW is used as the underlying mechanism in file systems like ZFS, Btrfs, ReFS, and Bcachefs,

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