A Virtual Machine (VM) is a program running on a conventional microprocessor that emulates the binary instruction set, registers, and memory space of an idealized computing machine, a well-known example being the Java Virtual Machine (JVM). Despite there being many binary Instruction Set Architectures (ISA) in existence, all share a set of core properties which have been tailored to their particular applications. An abstract model may capture these generic properties and be subsequently refined to a particular machine, providing a reusable template for development of formally proven ISAs: this is a task to which the EventB [16,18] notation is well suited. This paper describes a project to use the RODIN tool-set  to perform such a process, ultimately producing the MIDAS (Microprocessor Instruction and Data Abstraction System) VM, capable of running binary executables compiled from high-level languages such as C . The abstract model is incrementally refined to a model capable of automatic translation to C source code, and compilation for a hardware platform using a standard compiler. A second C compiler, targeted to the VM itself, allows C programs to be executed on it.