There will be a conference talk at BCTCS 2020, if it is still going ahead, on alpha-rams in April :
The alpha-ram family - bit level models for parallelism and concurrency.
There are no bit-level machine models for parallelism and concurrency, amongst the standard formal models of computation, that permit computer simulations in tractable amounts of time and space, for the investigation of not just trivial programming constructs, but also more complex high level programs. Such a machine would provide a basis for investigating processes running on a basic device rather than in a formalism abstracted from hardware, without introducing biases from the particulars of higher level architectures. The α-Ram family of deterministic machines provide not only simple semantics and neutral machine platforms for language design, but also opportunities for developing specialized and more general purpose architectures. Physical constraints can be incrementally introduced into the design process in a least restrictive order, thereby reducing bias towards pre-conceived architectural types.