Ex-Garmin engineer here. There are pockets of the company that use Android, and a bunch of the larger-scale systems have moved to using embedded Linux with Yocto.
The proprietary RTOS that runs on the watches is a super cool embedded system dating back to the earliest days of the company. It grew across all the product lines - watches, nav units, aviation equipment, marine chartplotters/sensors, etc. I remember once stumbling on some code written in the very early days by an engineer who went on to be the CEO while I was there.
It was a fun system to work on, and had an impressive amount of code sharing at the OS-level across platforms as tiny as Cortex M0 systems up to large multi-core ARM SoCs from TI and other vendors.
Thanks for the glimpse! My personal Garmin angle is cycling, which eventually that also "infected" my left wrist. When they first came under pressure in cycling from leaner competitors that are deep into the outsourcing game, I was interested to the point of pre-ordering. But since then I've learned more about the company and have come to respect them in an entirely unexpected way, for being that almost anachronistic twentieth century remnant that just keeps staying in the high tech innovation game. The mix of continuity and openness to change you describe sounds just right for that.
The proprietary RTOS that runs on the watches is a super cool embedded system dating back to the earliest days of the company. It grew across all the product lines - watches, nav units, aviation equipment, marine chartplotters/sensors, etc. I remember once stumbling on some code written in the very early days by an engineer who went on to be the CEO while I was there.
It was a fun system to work on, and had an impressive amount of code sharing at the OS-level across platforms as tiny as Cortex M0 systems up to large multi-core ARM SoCs from TI and other vendors.