File Management System Notes – File Access, Allocation Methods & Directory Structures

This unit explains how operating systems organize, access, and store files. It covers file attributes (name, type, size, location) and core operations (create, write, read, delete), followed by three File Access Methods — Sequential, Direct, and Indexed — with their working and trade-offs. File Allocation Methods are explained next: Contiguous, Linked, and Indexed Allocation, each illustrated with disk-block diagrams and directory tables. Finally, the three Directory Structures — Single-Level, Two-Level, and Tree-Structured — are compared with labeled diagrams, showing how each organizes files for single or multiple users along with their respective advantages and disadvantages.