Atomic snapshots of shared memory

An atomic snapshot memory is a shared data structure allowing concurrent processes to store information in a collection of shared registers, all of which may be read in a single atomic scan operation. This paper presents three wait-free implementations of atomic snapshot memory. Two constructions implement wait-free single-writer atomic snapshot memory from wait-free atomic single-writer, n-reader registers. A third construction implements a wait-free n-writer atomic snapshot memory from n-writer, n-reader registers. The first implementation uses unbounded (integer) fields in these registers, while the other implementations use only bounded registers. All operations require Θ(n²) reads and writes to the component shared registers in the worst case.