02030nas a2200289   4500000000100000000000100001008004100002260001200043653002000055653002000075653002100095653000900116100002500125700001900150700001700169700002400186700001700210700001500227700001800242700001800260245007000278856009800348300001000446490000600456520126400462022001401726       2014                            d  c06/201410aFault Tolerance10aMobile Services10aData Replication10aRoam1 aVijay Bhaskar-Semwal1 aMeenakshi Sati1 aVivek Vikash1 aVishwanath Bijalwan1 aPinki Kumari1 aManish Raj1 aMeenu Balodhi1 aPriya Gairola00aA Fault-Tolerant Mobile Computing Model Based On Scalable Replica  uhttp://www.ijimai.org/journal/sites/default/files/files/2014/03/ijimai20142_6_7_pdf_73533.pdf  a58-680 v23 aThe most frequent challenge faced by mobile user is stay connected with online data, while disconnected or poorly connected store the replica of critical data. Nomadic users require replication to store copies of critical data on their mobile machines. Existing replication services do not provide all classes of mobile users with the capabilities they require, which include: the ability for direct synchronization between any two replicas, support for large numbers of replicas, and detailed control over what files reside on their local (mobile) replica. Existing peer-to-peer solutions would enable direct communication, but suffers from dramatic scaling problems in the number of replicas, limiting the number of overall users and impacting performance. Roam is a replication system designed to satisfy the requirements of the mobile user. Roam is based on the Ward Model, replication architecture for mobile environments. Using the Ward Model and new distributed algorithms, Roam provides a scalable replication solution for the mobile user. We describe the motivation, design, and implementation of Roam and report its performance. Replication is extremely important in mobile environments because nomadic users require local copies of important data.   a1989-1660