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Types of File System

Types of File System

There are general two types of file sysytem -
» File Allocation table (FAT)
» New Technology file system (NTFS)

File Allocation table (FAT)

A file allocation table (FAT) is a table that an operating system maintains on a hard disk that provides a map of the clusters (the basic units of logical storage on a hard disk) that a file has been stored in. When you write a new file to a hard disk, the file is stored in one or more clusters that are not necessarily next to each other; they may be rather widely scattered over the disk. A typical cluster size is 2,048 bytes, 4,096 bytes, or 8,192 bytes. The operating system creates a FAT entry for the new file that records where each cluster is located and their sequential order. When you read a file, the operating system reassembles the file from clusters and places it as an entire file where you want to read it. For example, if this is a long Web page, it may very well be stored on more than one cluster on your hard disk.

New Technology file system (NTFS)

NTFS is a file system introduced by Microsoft and it has a number of advantages over the previous file system, named FAT32 (File Allocation Table).
Notable features of NTFS include :
• Use of a b-tree directory scheme to keep track of file clusters
• Information about a file's clusters and other data is stored with each cluster, not just a governing table (as FAT is)
• Support for very large files (up to 2 to the 64th power or approximately 16 billion bytes in size)
• An access control list (ACL) that lets a server administrator control who can access specific files
• Integrated file compression
• Support for names based on Unicode
• Support for long file names as well as "8 by 3" names
• Data security on both removable and fixed disks