Files is one of the components of an operating system security, show with example how file permission in Unix operating system provide layer of security?

Facts: Facts about Deadlock Deadlock is a situation that occurs in OS when any process enters a waiting state because another waiting process is holding the demanded resource. Deadlock is a common problem in multi-processing where several processes share a specific type of mutually exclusive resource known as a soft lock or software. Deadlock is a situation where a process or a set of processes is blocked, waiting for some other resource that is held by some other waiting process. It is an undesirable state of the system. The following are the four conditions that must hold simultaneously (Links to an external site.) for a deadlock to occur. Mutual Exclusion –A resource can be used by only one process at a time. If another process requests for that resource then the requesting process must be delayed until the resource has been released. Hold and wait –Some processes must be holding some resources in nonshareable mode and at the same time must be waiting to acquire some more…

Directories can be implemented either as "special files" that can only be accessed in limited ways, or as ordinary data files. What are the advantages and disadvantages of each approach?

How do directories support and manage file-level permissions and attribute flags in UNIX-based systems?