Abstract
This presentation by Dan J. Williams of Intel Corporation updates his presentation at PIRL 2019 where he told the story of surviving an encounter with the 3rd rail of Linux filesystems. While that survival felt like a capstone event that established “The Programming Model” in Linux it left a series of unanswered questions and feature requests in its wake. To this day, mounting a filesystem in DAX mode throws an “EXPERIMENTAL” warning to the system log. What remaining challenges warrant that continued designation? From a wider view, what does a kernel practitioner see as the next opportunities for Linux to better support the industry’s “experiment” with persistent memory?