Filesystems may be tightly coupled to OS, some more than others. 
  Some effort exists to change this.

Tightly coupled :

  Windows - XP,7,etc - NTFS (new technology filesystem)
    Also tightly coupled to Intel x86 cpu or Itanium 
    (some exceptions)
  
  MacOS - HFS Plus - modeled after FreeBSD
    Originally, Motrola 680x0, then IBM PowerPC, now Intel x86    

  MVS - IBM mainframe architecture.
     
  IBM OS/2 - HPFS - similar to NTFS and parent to it, written by MS for IBM. 
    Used a b+ tree hierarchical structure for storing/accessing directories.

  Solaris(Sun) Unix - primarily extension of the original AT&T Unix.

More loosly coupled.
  MS-DOS - FAT 12,16,32 - because of simplicity, FAT has become popular for 
    storage devices that move between OSes and system architectures.

    Originally tightly coupled to Microsoft OS/Intel cpu.
 
  Linux - ext2,ext3,Reiser,etc. Most filesystem protocols are available to
    all versions of Linux and a Linux system may access different partitions 
    with different filesystems on them.

  Various Unix systems - SunOS, BSD - user interface reasonably standardized,
    but OS/hardware side customized to system design.

  Database filesystems. Database programs may use custom filesystem protocols 
    which optimize the way they search, access, and manipulate data stored. 

    These may sit on top of a particular OS's filesystem or may act 
    independently and require exclusive access to a particular partition.

    Much of Journaling evolved from database systems.

  Others  (see wikipedia : filesystem, comparison of filesystems )  

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