In the early days of the collaboration between Bdale Garbee and Keith Packard that later became Altus Metrum, the software for TeleMetrum was crafted as an application running on top of an existing open source RTOS. It didn't take long to discover that the RTOS was ill-suited to our needs, and Keith had to re-write various parts of it to make things fit in the memory available and work at all.

Eventually, Bdale idly asked Keith how much of the RTOS he'd have to rewrite before it would make sense to just start over from scratch. Keith took that question seriously, and after disappearing for a day or so, the first code for AltOS was committed to revision control on 12 April 2009.

Ten years later, AltOS runs on multiple processor architectures, and is at the heart of all Altus Metrum products.