Please help

Time left 1:41:22 The ABC bank has dozen branch offices as well as its corporate HQ in a large metropolitan area. A customer opens an account at a particular branch and carries out a majority of his or her banking at that branch. Recently the bank installed a distributed processing system for handling daily transactions. Each branch has its own mini computer and there is a large centralized computer at corporate headquarters. The mini computers have communications with each other through a message switching via the central computer. The objectives of the system are to have online updating of all accounts and a highly secure transaction control and audit system at minimum cost. Each branch is sent each morning from the central computer a clean up-to-date copy of its file of documents. During the day all transactions on that branch's accounts are updated online on its file. Any transaction pertaining to an account at another branch is updated online at the appropriate minicomputer via the communication network. At night each branch's transaction log is transmitted to the central computer site which contains a master account file of all the branches. The same transactions are used to update the accounts in batch and the results are compared to the results of the day's local processing at each branch. All discrepancies are recorded in an error log for follow-up and clarification. The central file is considered the correct, permanent record of all accounts. At the beginning of the next day, the clean copies of local files are again downloaded from the central site to the branch for the day's processing. Questions: a) Why do you think multiple copies of the files are kept? b) Can you think of a situation where the online updating system could result in account discrepancies? Explain. (5+10 = 15 Marks)