Linked Allocation :
- Each file is a linked-list of disk-blocks.
- The disk-blocks may be scattered anywhere on the disk.
- The directory contains a pointer to the first to the first and the last blocks of the file.
- To create a new file, just create a new entry in the directory:
1) A write to the file causes a free block to be found. This new block is then written to and linked to the end of file.
2) A read to the file causes moving the pointers from block to block.
Advantages of Linked Allocation :
- There is no external fragmentation and in these free block on the free-space list can be used to satisfy a request.
- The size of the file doesn't need to be declared on creation.
- There is no necessary to compact disk-free.
Disadvantages of Linked Allocation :
- It can be used effectively only for sequential-access files.
- There is need of space that is required for the pointers.
- There is problems of reliability i.e if the pointer is lost.
