A simple wait-free construction of 1-writer multireader multivalued atomic variable from multireader regular variables is presented in this paper. A key point of the construction is the use of an elegant forwarding technique to overcome the new-old inversion property inherent in regular variables.Another construction, using a different forwarding technique, is also given. This technique is a refinement of one proposed in the literature. Formal correctness proofs for both the constructions are short and easy to follow.

Shared registers are basic objects used as communication mediums in asynchronous concurrent computation. A concurrent timestamp system is a higher typed communication object, and has been shown to be a powerful tool to solve many concurrency control problems. It has turned out to be possible to construct such higher typed objects from primitive lower typed ones. The next step is to find efficient constructions. We propose a very efficient wait-free construction of bounded concurrent timestamp systems from 1-writer shared registers. This finalizes, corrects, and extends a preliminary bounded multiwriter construction proposed by the second author in 1986. That work partially initiated the current interest in wait-free concurrent objects, and introduced a notion of discrete vector clocks in distributed algorithms.

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