Continuous allocation
advantage:
(1) Sequential access is easy
(2) Fast sequential access
Disadvantages:
(1) Requires continuous storage space
(2) Must know the length of the file in advance

Link assignment
advantage:
(1) Discrete allocation to eliminate external debris and improve utilization
(2) Suitable for dynamic growth of files at the same time; easy to modify
Disadvantages:
(1) Time cost of sequential retrieval: Cannot support efficient direct block access.
(2) Space cost of link information: FAT needs to occupy a large amount of memory space.

Index allocation
advantage:
(1) Support direct access
Disadvantages:
(1) Spending more external storage space