Galvin Edition 9 Exercise 11 Question 17 (Page No. 540)

Question

Some systems provide file sharing by maintaining a single copy of a
file. Other systems maintain several copies, one for each of the users
sharing the file. Discuss the relative merits of each approach

Comments

With a single copy, several concurrent updates to a file may result in user obtaining incorrect information, and the file being left in an incorrect state. With multiple copies, there is storage waste and the various copies may not be consistent with respect to each other