Compiling SHIM

Embedded systems demand concurrency for supporting simultaneous actions in their environment and parallel hardware. Although most concurrent programming formalisms are prone to races and nondeterminism, some, such as our shim (software/hardware integration medium) language, avoid them by design. In particular, the behavior of shim programs is scheduling-independent, meaning the I/O behavior of a program is independent of scheduling policies, including the relative execution rates of concurrent processes. The shim project demonstrates how a scheduling-independent language simplifies the design, optimization, and verification of concurrent systems. Through examples and discussion, we describe the shim language and code generation techniques for both shared-memory and messagepassing architectures, along with some verification algorithms.