OpenAtom OpenHarmony, or abbreviated as OpenHarmony (OHOS), is an open-source version of HarmonyOS donated by Huawei to the OpenAtom Foundation. Similar to HarmonyOS, the open-source operating system is designed with a layered architecture, which consists of four layers from the bottom to the top, i.e., the kernel layer, system service layer, framework layer, and application layer. The system contains the basic capabilities of HarmonyOS.