We extend a torus-based coterie structure for distributed mutual exclusion to allow k multiple entries in a critical section. In the original coterie, the system nodes are logically arranged in a rectangle, called a torus, in which the last row (column) is followed by the first row (column) using end wraparound. A torus quorum consists of a head and a tail, where the head contains one entire row and the tail contains one node from each of the s succeeding rows, s 1 is a system parameter. It has been shown that by setting s= h / 2 , where h = the number of rows, the collection of torus quorums form an equal-sized, equal-responsibility coterie. In this paper, we propose two extensions to kcoteries: The Div-Torus method divides the system nodes into k clusters and runs a separate instance of a torus coterie in each cluster; the k-Torus method uses quorums of tail s= h k/ ( )+1 . We compare the quorum size and quorum availability of the two proposed methods, and against the DIV method w...
S. D. Lang, L. J. Mao