What is FAT & they types

What is FAT & they types

1. FAT is an acronym for File Allocation Table. This table provides the index of the files in the system and is statically allocated at the time of formatting the drive. It contains an entry for each cluster (a data storage area).

   • https://www.keil.com/pack/doc/mw/FileSystem/html/fat_fs.html#:~:text=FAT%20is%20an%20acronym%20for,(a%20data%20storage%20area).

2. Types of FAT partition's

   • About FAT File System
     • https://www.partitionwizard.com/partitionmagic/fat-vs-fat32.html
     • FAT, short for File Allocation Table, is a file system originally developed in 1977 for use on floppy disks. And it was later adapted for use on hard disks and other devices.
       • The first FAT version is 8-bit FAT released in 1977 and it was only used in some terminal computer systems at that time. Therefore, it was not widely used. In 1980, FAT12 was released, along with the first version of DOS. It is the first widely used version of the FAT file system.
         • In 1984, FAT16 was released and in the next few years Microsoft released FAT16 improved versions (FAT16B and FAT16X). But all of them are called FAT16. In 1996, FAT32 was released for Windows 95 OSR2 / MS-DOS 7.1.
           • Please note that 8-bit FAT, FAT12, FAT16, and FAT32 are variants of the FAT file system. The reason why Microsoft releases new FAT file systems is that the old FAT file system can’t manage so large a disk as disk drive capacity increases.
   • FAT12 vs FAT16 vs FAT32: Size Limit
     • When you create a partition, the FAT32 option only occurs when the partition is no more than 32GB and the FAT option only occurs when the partition is smaller than 4GB. If you have created a FAT partition, the partition is FAT16 when the volume size is no smaller than 16MB; and the partition becomes FAT12 when it is smaller than 16MB.
       • Please note that in Windows 10, the minimum volume size is 8MB and you can’t create a FAT8 partition.
         • Therefore, when it comes to FAT32 vs FAT, I must explain FAT12 vs FAT16 vs FAT32 actually. To understand FAT12 vs FAT16 vs FAT32 standards, please refer to the following chart:
           • The specific minimum volume size and maximum volume may vary from computer to computer. In my PC (the system is Windows 10 and the disk sector size is 512 bytes), the boundary between FAT12 and FAT16 is 16 MB; the maximum size of FAT16 is 4 GB; and the minimum volume size of FAT32 is 36 MB.
             • If I want to create a FAT32 partition smaller than 36MB, I will get error message “The volume size is too small for the selected file system” and then the partition becomes a RAW partition.
   • FAT File Systems. FAT32, FAT16, FAT12
     • https://www.ntfs.com/fat_systems.htm
     • The File Allocation Table (FAT) file system is a simple file system originally designed for small disks and simple folder structures.
       • The FAT file system is named for its method of organization, the file allocation table, which resides at the beginning of the volume. To protect the volume, two copies of the table are kept, in case one becomes damaged.
         • In addition, the file allocation tables and the root folder must be stored in a fixed location so that the files needed to start the system can be correctly located.
           • A volume formatted with the FAT file system is allocated in clusters. The default cluster size is determined by the size of the volume. For the FAT file system, the cluster number must fit in 16 bits and must be a power of two.
             • Structure of a FAT Volume
               • The figure below illustrates how the FAT file system organizes a volume.
             • FAT Partition Boot Sector
               • https://www.ntfs.com/fat-partition-sector.htm
               • The Partition Boot Sector contains information that the file system uses to access the volume. On x86-based computers, the Master Boot Record use the Partition Boot Sector on the system partition to load the operating system kernel files. The table describes the fields in the Partition Boot Sector for a volume formatted with the FAT file system.
             • FAT32 Partition Types
               • https://www.ntfs.com/fat-part-types.htm
               • The following table displays all valid partition types and their corresponding values for use in the Part_FileSystem member of the s_partition structure.
               • Most compatible operating system

3. INTRODUCTION

   • File system is a simple file system originally designed for small disks and simple folder structures. The FAT file system is named for its method of organization, the file allocation table, which resides at the beginning of the volume. To protect the volume, two copies of the table are kept, in case one becomes damaged. In addition, the file allocation tables and the root folder must be stored in a fixed location so that the files needed to start the system can be correctly located. A volume formatted with the FAT file system is allocated in clusters. The default cluster size is determined by the size of the volume. For the FAT file system, the cluster number must fit in 16 bits and must be a power of two.

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