Minimal shared information for concurrent reading and writing

While there have been many register construction algorithms in the recent years, results establishing the intrinsic complexity of such constructions are scarce. In this paper, we establish the minimum shared memory necessary to construct an atomic single-writer, single-reader, N-bit register A from single-writer, single-reader, single bit safe registers. The write operation on A is wait-free, but the read operation is not. We also provide constructions that match our lower bounds.