There was talk about their move away from FreeBSD several years ago. They started as Berkeley Software Design in the early 1990's, hence the BSD acronym. Time's a changin.
TrueNAS CORE Bids Goodbye To FreeBSD - PC PerspectiveTrueNAS CORE Bids Goodbye To FreeBSD The current TrueNAS CORE 13 will be the last FreeBSD-based NAS from iXsystems. From now you will see the OS of the