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FAT Full Form

Read this article to know about the full form of FAT, its history, types, uses, and limitations.

FAT stands for File Allocation Table. It is the computer system files architecture that is now extensively employed on the majority of computer systems and memory cards. The Memory Allocation Table on a computer drive indicates which sections are used for which files. The File Allocation Table (FAT, FAT16, and FAT32) is found in the guide partition sector of a bootable, floppy disc or hard drive.

Table of Contents

  1. History of FAT
  2. Types of FAT
  3. Uses of FAT
  4. Limitations of FAT

History of FAT

FAT was initially introduced in Bios and Windows 9x via hard drives. IBM released FAT16 with IBM’s desktop pc AT (PC AT) and Microsoft’s MS-DOS (disc os) 3.0 software in 1983. Compaq DOS 3.31 offered an enhancement of the initial FAT16 in 1987, increasing the number of disc sectors to 32 bits. Because the disc was originally developed for a 16-bit assembler, it had to be modified to utilise 32-bit sector codes. Microsoft introduced FAT32 in 1997. This FAT file format extended capacity restrictions and made DOS real mode software capable of handling the format. FAT32 contains a 32-bit cluster address, with the remaining 28 bits used to store the cluster identifier for up to 268 million clusters. 

Types of FAT

  • 8-bit FAT8- Based on conversations between McDonald’s and Bill Gates, Marc Donald devised and implemented the initial FAT file system. It debuted in 1977 or 1978 with 8-bit table elements. Microsoft’s Z80 platforms also utilised the FAT data file in 1978.
  • 12-bit FAT12 – The cluster address is stored in FAT12 using 12-bit elements. Some values were set aside to indicate the end of a cluster sequence or unusable disc areas. As a result, the maximum number of clusters was set at 4078.
  • 16- bit FAT16 – Cluster addresses were raised to 16 bits, enabling up to 65,526 groups; nevertheless, the maximum number of sectors and division size of 32 MB remained the same. Even though cluster locations remained 16 bits, this structure was not widely referred to as FAT16.

Uses of FAT

FAT remained the norm for all homeowners until NT-based Win Xp in 2001. Microsoft Windows later introduced a capability that is a pre-installed program that directly transforms a FAT file system to NTFS. Some of the advantages of FAT are:

  • It achieves files without having to rewrite any of the documents. However, it cannot be reversed directly.
  • It supports partition sizes of up to 8TB.
  • FAT stores its data throughout the full disc block.
  • Because it is the earliest 3-file system accessible for Windows OS, it is used by various manufacturers, including gaming systems and USB drives.
  • FAT is suitable for most operating systems, including macOS, Linux, and Windows.
  • The FAT32 file system offers simpler conversion methods.
  • A single faulty disc does not result in the loss of subsequent blocks.
  • FAT also provides random access.

Limitations of FAT

The FAT approach also has the following drawbacks:

  • It has several partitions that aren’t supported or detected.
  • Only files accessed in reading mode can have several active file handles.
  • For FAT, the total route length is still only 260 bytes. Because of the ANSI C Standards library’s fseek and ftell limitations, searching within documents is limited to two gigabytes.
  • It does not accept UTF 16 or UTF 8 characters.