# The programs written on these machines are, in general, of type [[SIMD]].
These kinds of caarealgorithms are useful for understanding the exploitation of concurrency, dividing the original problem into similar sub-problems and solving them in parallel. The introduction of the formal 'P-RAM' model in Wyllie's 1979 thesis<ref>Wyllie, James C. The Complexity of Parallel Computations, PhD Thesis, Dept. of Computer Science, Cornell University</ref> had the aim of quantifying analysis of parallel algorithms in a way analogous to the [[Turing Machine]]. The analysis focused on a MIMD model of programming using a CREW model but showed that many variants, including implementing a CRCW model and implementing on an SIMD machine, were possible with only constant overhead.
