The three file allocation methods
1. Contiguous allocation: A single continuous block is allocated to a file at a time of file creation. It is the best for individual sequential file.
2. Chained allocation: Allocation is on an individual block basis. Each block contains a pointer to the next block in the chain.
3. Indexed allocation: A file allocation table contains a separate one-level index for each file; the index has one entry for each portion allocated to the file.