2 ms·iOS is based on Darwin/XNU. These are all the upper layers that are closed-source.by snippyhollow 16y agoiOS is based on Darwin/XNU. These are all the upper layers that are closed-source.1amzave 16y agoIf I'm remembering correctly, the ARM port of XNU is not open-source though.Xuzz 16y agoIt's not very different.