Diagnosability of hypercubes and enhanced hypercubes under the comparison diagnosis model

A. Sengupta and A. Dahbura (1992) discussed how to characterize a diagnosable system under the comparison diagnosis model proposed by J. Maeng and M. Malek (1981) and a polynomial algorithm was given to identify the faulty processors provided that the system´s diagnosability is known. However, for a general system, the determination of its diagnosability is not algorithmically easy. This paper proves that, for the important hypercube structured multiprocessor systems (n-cubes), the diagnosability under the comparison model is n when n⩾5. The paper also studies the diagnosability of enhanced hypercube, which is obtained by adding 2^n-1 more links to a regular hypercube of 2ⁿ processors. It is shown that the augmented communication ability among processors also increases the system´s diagnosability under the comparison model. We prove that the diagnosability is n+1 for an enhanced hypercube when n⩾6