Screenshot of Linux kernel source code defining various memory devices as files, where they all have one "file operations" (fops) functions. They are respectively mem fops, null fops, port fops, zero fops, full fops, random fops, urandom fops, and kmsg fops.
https://eldritchcafe.files.fedi.monster/media_attachments/files/113/158/750/325/842/192/original/559e7271f3c90695.png