Vulkan is an explicit API, enabling direct control over how GPUs actually work. As such, Vulkan supports systems that have multiple GPUs, each running with a different driver, or ICD (Installable Client Driver). Vulkan also supports multiple global contexts (instances, in Vulkan terminology). The ICD loader is a library that is placed between a Vulkan application and any number of Vulkan drivers, in order to support multiple drivers and the instance-level functionality that works across these drivers. Additionally, the loader manages inserting Vulkan layer libraries, such as validation layers, between an application and the drivers. WWW: https://github.com/KhronosGroup/Vulkan-Loader