With contiguous allocation, each file occupies contiguous blocks on the disk. The location of a file is defined by the disk address of the first block and its length.

A file allocated disk space using contiguous allocation method

Pros

• Both sequential access and direct/Random access are supported by the contiguous allocation.
• Internal fragmentation may exist in the last disk block of a file.

Cons

• Difficult to increase the size of a file as the next contiguous block may not be free.
• External fragmentation