We describe the architecture of a virtual machine for executing
functional logic programming languages. A distinguishing feature
of our machine is that it preserves the operational completeness
of non-deterministic programs by concurrently executing a pool of
independent computations. Each computation executes only
root-needed sequential narrowing steps. We describe the machine's
architecture and instruction set; and show how to compile
overlapping inductively sequential programs to sequences of
machine instructions. The machine has been implemented in Java and
in Standard ML.