We anticipate that, by 2020, the basic unit of warehouse-
scale cloud computing will be a rack-sized machine instead
of an individual server. At the same time, we expect a
shift from commodity hardware to custom SoCs that are
specically designed for the use in warehouse-scale comput-
ing. In this paper, we make the case that the software for
such custom rack-scale machines should move away from the
model of running managed language workloads in separate
language runtimes on top of a traditional operating system
but instead run a distributed language runtime system capa-
ble of handling dierent target languages and frameworks.
All applications will execute within this runtime, which per-forms most traditional OS and cluster manager functionality such as resource management, scheduling and isolation.