File system is the most vital part for every operating system to save the data on drives in a proper way so that if user search for a file then he can access that file immediately. Besides, it controls how data is stored and retrieved. Windows operating system has mainly two file system FAT and NTFS. The very first file system introduced by Microsoft was FAT (File allocation table) afterwards its upgraded versions FAT16, FAT32 came with enhanced features. We are discussing here about the FAT file system, its working, and versions of FAT and their limitations.
File Allocation Table (FAT) file system is a table which is used by Windows Operating system to control and locate the files on a hard disk and provides a mapping to clusters (a logical storage space on hard disk). When we create a file on a hard disk it stores anywhere in clusters in a scattered way. FAT system helps OS to track all the scattered pieces in clusters and make them readable for the user.
Windows FAT file system is basically based on the linked list, means each file which is stored in clusters has the pointer to its next cluster.
Overview of FAT File System
File Allocation Table (FAT) file system is a table which is used by Windows Operating system to control and locate the files on a hard disk and provides a mapping to clusters (a logical storage space on hard disk). When we create a file on a hard disk it stores anywhere in clusters in a scattered way. FAT system helps OS to track all the scattered pieces in clusters and make them readable for the user.
Windows FAT file system is basically based on the linked list, means each file which is stored in clusters has the pointer to its next cluster.
In this picture there is three files File1.txt has 3 clusters with address of its next cluster, File2.txt is fragmented which is also using 3 clusters and File3.txt is small so it fits in a single cluster.
Different versions of Windows File allocation table and their features are given below:
The very first version of FAT file system was known as FAT12, which supports a maximum partition size of 8MB. FAT12 is basically introduced for Floppy disks. It was very limited because it used 12 bit value to store the only 4078 clusters.
Versions of FAT File System
Different versions of Windows File allocation table and their features are given below:
Windows File System FAT12
The very first version of FAT file system was known as FAT12, which supports a maximum partition size of 8MB. FAT12 is basically introduced for Floppy disks. It was very limited because it used 12 bit value to store the only 4078 clusters.
Windows File System FAT16
- FAT16 was introduced to overcome the FAT12 limitations.
- FAT16 came with the cluster value size with 16 bits 65,517 clusters. It also allows up to 2GB partition. The main advantage of FAT16 is that it is compatible with many variety of operating systems like windows95/98/Me.
Advantages of FAT16
- FAT16 is used by MS-DOS, Windows 95, Windows 98, Windows NT, Windows 2000, and some UNIX operating systems can also use it.
- If you can’t startup your system, then you can use MS-DOS bootable floppy disk to start your system.
- This version of FAT file system performs in the best possible way, on volumes smaller than 256 MB, in speed and storage.
Disadvantages of FAT16
- FAT16 has limited storage space. To maintain the compatibility with MS-DOS, Windows 95, and Windows 98, a FAT16 volume should not be larger than 2 GB.
- In FAT16 there is no file security and no file compression.
- In FAT16, if data stored on volumes is lost by some technical issue then there is no backup of data on boot sector.
Windows File System FAT32
FAT32 file system was an improvement over its predecessor FAT16 and it was introduced with windows 95/98/Me. It supports up to 2TB drives excludes Windows 2000 which supports size up to 32 GB in FAT32.
- FAT32 file system uses the space in a very effective manner. It uses smaller cluster that is 4kb for the drive up to 8GB, which results the more efficiently use of disk comparing to FAT12 and FAT16.
Advantages of FAT32
- FAT 32 file system came with some noticeable features that are given below:
- FAT32 uses space more efficiently than FAT16, it uses smaller clusters to perform effectively.
- FAT32 file system has the ability to relocate the root directory, and uses the duplicate copy file instead of default copy. Which means FAT32 is less susceptible to failure.
Disadvantages of FAT32
- Boot Sector has no backup.
- In FAT32 there is no built in security and compression.
- The size of clusters can’t be more than 64kb.
- In windows 2000 you can’t format a disk larger than 32 GB in FAT32 system. It shows an error “Logical Disk Manager: Volume size too big.”
Limitations of Windows File Allocation System
- File allocation system is a kind of file system which can’t works with the large disks.
- FAT file system has no inbuilt active directory and domain based Security.
- It doesn’t provides file compression.
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