The Layered File System

• Applications Programs : High level language interface to files :
  Common access methods : Sequential, Random and Indexed Sequential
• Logical File System (Directory Level) : Mapping from symbolic names to file locations (i.e. supports directory system) ... more on this later
• File Organisation Module : Allocation and management of file space (free space etc)
• Basic or Flat File System : Basic file access facilities (read, write a block of file via a single level - flat directory structure). Block address to disk address translation (e.g. drive, cylinder, surface, sector)
• I/O Control : Device drivers and interrupt handlers (transfer of physical blocks of data between disk and memory)
• Devices : Disks on which files are stored

Archive Services : run as application programs
How can files be accessed from the programs (application) by the user ?