A File System is the way of organizing and storing the data's contained in files for easy accessing and processing. A files system makes use of storage devices like hard disk and also involves the management of these files in their physical locations. The clients of a network protocol can access the data on a file server. A file System contains a set of abstract data types, which are used in manipulation and navigation purposes. File systems are classified on the basis of Data Base Management Systems (DBMS), as they are data base oriented. The different types of file systems are,
1. Disk File Systems.
2. Data Base File Systems.
3. Network File Systems.
4. Transactional file Systems.
The Disk File Systems are used for the storage of data on storage devices. Example: FAT (File Allocation Table), HFS (Hierarchical File Systems). In Data base File Systems, the files are accessed using the information stored in metadata. In Transactional File Systems, the changes we make in files can also modify the disk structures. Hence, it can be solved by resynchronization. A Network File System (NFS) involves sharing of files over a network. The other resources like printers, and etc. can also be shared over a network. Hence, these are called Network File Systems. The first widely used distributed file system was NFS, created by Sun Microsystems in the year 1985. In Distributed File System (DFS), there are multiple storage devices.
The users need not know about the procedure of storing information on the disk, as it is mandatory that the information is stored on non-contiguous memory allocation. Now, file systems are integral part of modern Operating Systems where as previously, there was a separate operating system to handle file systems called, Disk Operating Systems. The file systems are essential to organize the sectors or fixed-blocks of information in to files and directories. The directories will contain the file names of the files stored and using File Allocation Table these are indexed. The files can be accessed through the path of the location it is stored. The Directory structures can be flat or hierarchical and also can contain sub-directories. Thus, file system are focused on the storage and retrieval of data.
