virtual file system (VFS)

http://www.ibm.com/developerworks/library/l-virtual-filesystem-switch/

http://www.linfo.org/hard_link.html

http://www.ibm.com/developerworks/linux/library/l-linux-filesystem/

https://www.kernel.org/doc/Documentation/filesystems/vfs.txt

https://www.thomas-krenn.com/de/wikiDE/images/2/2d/Linux-storage-stack-diagram_v4.0.pdf

https://en.wikipedia.org/wiki/Virtual_file_system

https://www.ibm.com/developerworks/cn/linux/l-vfs/

https://www.ibm.com/developerworks/library/l-virtual-filesystem-switch/

http://www.linux.it/~rubini/docs/vfs/vfs.html

http://lxr.free-electrons.com/source/Documentation/filesystems/vfs.txt

https://www.kernel.org/doc/Documentation/filesystems/vfs.txt

https://www.mimuw.edu.pl/~vincent/lecture12/12-fs.pdf

http://www.inf.fu-berlin.de/lehre/SS01/OS/Lectures/Lecture16.pdf

http://www.cs.columbia.edu/~krj/os/lectures/L21-LinuxVFS.pdf