Date Added: Feb 2013
In a distributed storage network, reliability and bandwidth optimization can be provided by regenerating codes. Recently table based regenerating codes viz. DRESS (Distributed Replication-based Exact Simple Storage) codes has been proposed which also optimizes the disk I/O. Dress codes consists of an outer MDS code with an inner Fractional Repetition (FR) code with replication degree. Several constructions of FR codes based on regular graphs, resolvable designs and bipartite graphs are known. This paper presents a simple modular construction of FR codes. The authors also generalize the concept of FR codes to Weak Fractional Repetition (WFR) codes where each node has different number of packets. They present a construction of WFR codes based on partial regular graph.