text: We present two algorithms for the Group Mutual Exclusion (GME) Problem that satisfy the properties of Mutual Exclusion, Starvation Freedom, Bounded Exit, Concurrent Entry and First Come First Served. Both our algorithms use only simple read and write instructions, have O(N) Shared Space complexity and O(N) Remote Memory Reference (RMR) complexity in the Cache Coherency (CC) model. Our first algorithm is developed by generalizing the well-known Lamport's Bakery Algorithm for the classical mutual exclusion problem, while preserving its simplicity and elegance. However, it uses unbounded shared registers. Our second algorithm uses only bounded registers and is developed by generalizing Taubenfeld's Black and White Bakery Algorithm to solve the classical mutual exclusion problem using only bounded shared registers. We show that contrary to common perception our algorithms are the first to achieve these properties with these combination of complexities.
  @cite_9: Group mutual exclusion is an interesting generalization of the mutual exclusion problem. This problem was introduced by Joung, and some algorithms for the problem have been proposed by incorporating mutual exclusion algorithms. Group mutual exclusion occurs naturally in a situation where a resource can be shared by processes of the same group, but not by processes of different groups. It is also called the congenial talking philosophers problem. In this paper we propose three algorithms based on ticket orders for the group mutual exclusion problem in the asynchronous shared memory model. The first algorithm is a simple modification of the Bakery algorithm. It satisfies group mutual exclusion, but does not satisfy lockout freedom. The second and the third algorithms are further modifications from the first one in order to satisfy lockout freedom and to improve the concurrency performance. They use single-writer shared variables, together with two multi-writer shared variables that are never concurrently written. The third algorithm has another desirable property, called smooth admission. By this property, during the period that the resource is occupied by the leader, a process wishing to join the same group as the leader's group can be granted use of the resource in constant time.
summary: Takamura and Igarashi also made an attempt in @cite_9 to generalize Lamport’s Bakery Algorithm to solve the GME problem. They presented three different algorithms in that paper. However, all of their algorithms satisfy neither the concurrent entry property nor the FCFS property.