A 10-minute guide to the Linux ABI
Many Linux enthusiasts are familiar with Linus Torvalds' famous admonition, "we don't break user space," but perhaps not everyone who recognizes the phrase is certain about what it means.
The "#1 rule" reminds developers about the stability of the applications' binary interface via which applications communicate with and configure the kernel. What follows is intended to familiarize readers with the concept of an ABI, describe why ABI stability matters, and discuss precisely what is included in Linux's stable ABI. The ongoing growth and evolution of Linux necessitate changes to the ABI, some of which have been controversial.