Named pipes are in fact FIFO's. These are persistent objects represented by nodes in the file system. A named pipe provides many-to-many, two-way communication between one or more processes that are not necessarily related and do not need to exist at the same time. The file name of the pipe serves as an address or contract between the processes for communication. If only one process writes to a named pipe and one other process reads from the named pipe, then the named pipe behaves in the same way as an unnamed pipe between the two related processes.
So the short answer is that you need a named pipe for communication between unrelated processes that might not exist at the same time.
Named pipes have three advantages:
1.) You don't have to start the reading/writing processes at the same time.
2. ) You can have multiple readers/writers which do not need common ancestry.
3.) As a file you can control ownership and permissions.
Regular pipes provide a means of one-to-one, one-way inter process communication between different processes that are related by either a parent-child relationship, or by being children of a common parent that provides the pipe, such as a shell process. Because the processes are related, the association of file descriptors to the pipe can be implicit and does not require an object with a name that is external to the processes.
