I started my career writing apps for the Mac 25 years ago, but 18 years ago switched to toolchains and later hard-core systems programming as well as databases

I started my career writing apps for the Mac 25 years ago, but 18 years ago switched to toolchains and later hard-core systems programming as well as databases and 3d graphics. I think the front vs back end distinction isn't sufficient, as someone doing Rails might be "back end" but certainly couldn't write and debug a device driver...