  The file system provides the mechanism for online storage and access to file
contents, including data and programs. This paper covers the high-level details
of file systems, as well as related topics such as the disk cache, the file
system interface to the kernel, and the user-level APIs that use the features
of the file system. It will give you a thorough understanding of how a file
system works in general. The main component of the operating system is the file
system. It is used to create, manipulate, store, and retrieve data. At the
highest level, a file system is a way to manage information on a secondary
storage medium. There are so many layers under and above the file system. All
the layers are to be fully described here. This paper will give the explanatory
knowledge of the file system designers and the researchers in the area. The
complete path from the user process to secondary storage device is to be
mentioned. File system is the area where the researchers are doing lot of job
and there is always a need to do more work. The work is going on for the
efficient, secure, energy saving techniques for the file systems. As we know
that the hardware is going to be fast in performance and low-priced day by day.
The software is not built to comeback with the hardware technology. So there is
a need to do research in this area to bridge the technology gap.
