Editing File Allocation Table (section)

===FAT32===
{{Infobox file system
| name                    = FAT32
| full_name             DEVICE1

[[Design of the FAT file system#FAT32|32-bit File Allocation Table]]<br />(with 28-bit cluster entries)
| developer               = [[Microsoft]], [[Caldera UK|Caldera]]
| variants = 
| introduction_date       = August 1996 ([[Windows 95 OSR2]])
| partition_id            = [[Master Boot Record|MBR]]/[[Extended Boot Record|EBR]]: {{ubli
 | [[#FAT32|FAT32]]: <code>{{abbr|0x|Values in C-notation for hexadecimal numbers}}[[Partition type#PID_0Bh|0B]]</code><code>[[Partition type#PID_0Ch|0x0C]]</code> ([[Logical block addressing|LBA]]), e.a.
 | [[Basic data partition|BDP]]: <code>EBD0A0A2-B9E5-4433-87C0-68B6B72699C7</code>
 }}
| directory_struct = 
| file_struct = 
| bad_blocks_struct = 
| min_volume_size         = {{ubli
 | 32&nbsp;[[megabyte|MB]] – 4.5&nbsp;[[kilobyte|KB]] (with 65525 clusters and 512 byte sectors)
 | 256&nbsp;MB – 36&nbsp;KB (with 65525 clusters and 4&nbsp;[[kilobyte|KB]] sectors)
 }}
| max_volume_size         = {{ubli
 | 2&nbsp;[[terabyte|TB]] (with 512&nbsp;byte sectors)
 | 8&nbsp;TB (with 2&nbsp;KB sectors and 32&nbsp;KB clusters)
 | 16&nbsp;TB (with 4&nbsp;KB sectors and 64&nbsp;KB clusters)
 }}
| max_file_size           = {{ubli
 | 2,147,483,647 bytes (2&nbsp;GiB − 1 byte)<!-- 2^31 - 1 --> (without [[large file support|LFS]])
 | 4,294,967,295 bytes (4&nbsp;GiB − 1 byte)<!-- 2^32 - 1 --><ref name="GB4" /> (with [[large file support|LFS]])
 | 274,877,906,943 bytes (256&nbsp;GiB − 1 byte)<!-- 2^38 - 1 --> (only with FAT32+<ref name="DRDOS_FAT+_R2" />)
 }}
| max_files_no            = 268,173,300 for 32&nbsp;KB clusters<!-- 2^28 − 12 (reserved clusters) − 262144 (number of 32&nbsp;KB clusters for directory entries) -->
| max_filename_size       = [[8.3 filename]] with [[OEM character set|OEM]] characters, <br />255 [[UCS-2]] characters<ref group="nb" name="NB_LFN_UNI"/> when using [[Long filename|LFN]]
| max_directory_depth     = 32&nbsp;levels or 66&nbsp;characters (with [[Current Directory Structure|CDS]]), <br />60&nbsp;levels or more (without CDS)
| dates_recorded          = {{ubli
 | Modified date/time, creation date/time (DOS&nbsp;7.0 and higher only),
 | access date (only available with [[ACCDATE (CONFIG.SYS directive)|ACCDATE]] enabled),<ref name="Microsoft_2006_ACCDATE" />
 | deletion date/time (only with DELWATCH 2<!-- with Novell DOS 7, Caldera OpenDOS 7.01, DR-DOS 7.02 and higher -->)
 }}
| date_range              = [[Epoch of 1980-01-01|1980-01-01]] to [[Year 2100 problem|2099-12-31]] ([[Year 2108 problem|2107-12-31]])
| date_resolution         = {{ubli
 | 2&nbsp;seconds for last modified time,
 | 10&nbsp;ms for creation time,
 | 1&nbsp;day for access date,
 | 2&nbsp;seconds for deletion time
 }}
| forks_streams = 
| attributes              = [[FAT file attributes|Read-only]], [[FAT file attributes|hidden]], [[FAT file attributes|system]], [[FAT file attributes|volume]], [[FAT file attributes|directory]], [[FAT file attributes|archive]]
| file_system_permissions = Partial, only with [[DR-DOS]], [[REAL/32]] and [[4690 OS]]
| compression             = Yes
| encryption              = 
| data_deduplication = 
| OS = 
| file_size_granularity   = 1&nbsp;byte
}}

In order to overcome the volume size limit of FAT16, while at the same time allowing DOS [[Real mode|real-mode]] code to handle the format, Microsoft designed a new version of the file system, '''FAT32''', which supported an increased number of possible clusters, but could reuse most of the existing code, so that the [[conventional memory]] footprint was increased by less than 5&nbsp;KB under DOS.<ref name="Microsoft_1998_CC768180" /> Cluster values are represented by [[32-bit]] numbers, of which 28 bits are used to hold the cluster number.

==== Maximal sizes ====
The FAT32 boot sector uses a 32-bit field for the sector count, limiting the maximal FAT32 volume size to 2&nbsp;[[terabyte]]s with a sector size of 512&nbsp;[[byte]]s. The maximum FAT32 volume size is 16&nbsp;TB with a sector size of 4,096&nbsp;bytes.<ref name="Microsoft_2007_KB184006" /><ref name="Microsoft_2007_KB314463" /> The built-in [[Windows shell]] disk format tool on Windows NT arbitrarily only supports volume sizes up to 32&nbsp;GB,{{refn|group="nb"|This was a decision taken by the developer in question, who assumed his decision would be revised later, something that never happened.<ref>{{cite web | url=https://www.theregister.com/2021/01/04/windows_format_fat32/ | title=Explained: The thinking behind the 32GB Windows Format limit on FAT32 }}</ref>}} but Windows supports reading and writing to preexisting larger FAT32 volumes, and these can be created with the [[command prompt]], [[PowerShell]] or third-party tools,<ref>{{Cite web |last=Glenn |first=Walter |title=How to Format USB Drives Larger Than 32GB With FAT32 on Windows |url=https://www.howtogeek.com/316977/how-to-format-usb-drives-larger-than-32gb-with-fat32-on-windows/ |access-date=2021-01-26 |website=How-To Geek |date=July 20, 2017 |language=en-US |archive-date=2021-01-26  |archive-url=https://web.archive.org/web/20210126003213/https://www.howtogeek.com/316977/how-to-format-usb-drives-larger-than-32gb-with-fat32-on-windows/ |url-status=live }}</ref> or by formatting the volume on a non-Windows system or on a Windows 9x system with FAT32 support and then transferring it to the Windows NT system. In August 2024, Microsoft released an update to Windows 11 preview builds that allows for the creation of FAT32 partitions up to 2TB in size.<ref>{{Cite web |author1=Roshan Ashraf Shaikh |date=2024-08-16 |title=Windows 11 preview build sees FAT32 partition size increased to 2TB after 30 years |url=https://www.tomshardware.com/software/operating-systems/windows-11-preview-build-sees-fat32-partition-size-increased-to-2tb-after-30-years |access-date=2024-08-23 |website=Tom's Hardware |language=en}}</ref> 

The maximal possible size for a file on a FAT32 volume is 4&nbsp;[[gigabyte|GB]] minus 1 byte, or 4,294,967,295 (2<sup>32</sup>&nbsp;−&nbsp;1) bytes. This limit is a consequence of the 4-byte file length entry in the directory table and would also affect relatively huge FAT16 partitions enabled by a sufficient sector size.

Like FAT12 and FAT16, FAT32 does not include direct built-in support for long filenames, but FAT32 volumes can optionally hold [[#VFAT|VFAT]] long filenames in addition to short filenames in exactly the same way as VFAT long filenames have been optionally implemented for FAT12 and FAT16 volumes.

==== Development ====
FAT32 was introduced with [[Windows 95]] OSR2(MS-DOS 7.1) in 1996, although reformatting was needed to use it, and [[DriveSpace 3]] (the version that came with Windows 95 OSR2 and Windows 98<!-- what about ME? -->) never supported it. [[Windows 98]] introduced a utility to convert existing hard disks from FAT16 to FAT32 without loss of data.

In the Windows NT line, native support for FAT32 arrived in [[Windows 2000]]. A free FAT32 driver for [[Windows NT 4.0]] was available from [[Winternals]], a company later acquired by Microsoft. The acquisition of the driver from official sources is no longer possible. Since 1998, Caldera's dynamically loadable [[DRFAT32]] driver could be used to enable FAT32 support in DR-DOS.<ref name="Caldera_1998_DRFAT32-RM"/><ref name="Caldera_1998_DRFAT32"/> The first version of DR-DOS to natively support FAT32 and LBA access was OEM DR-DOS 7.04 in 1999. That same year [[Intelligent Micro Software|IMS]] introduced native FAT32 support with [[REAL/32]] 7.90, and [[IBM 4690 OS]] added FAT32 support with version 2.<ref name="IBM_4690_User_Guide" /> [[Ahead Software]] provided another dynamically loadable FAT32.EXE driver for DR-DOS 7.03 with [[Nero Burning ROM]] in 2004.<!-- with copyrights 2002-2004 --> IBM introduced native FAT32 support with OEM PC DOS 7.1 in 1999.

Two partition types have been reserved for FAT32 partitions, <code>[[Partition type#PID 0Bh|0x0B]]</code> and <code>[[Partition type#PID 0Ch|0x0C]]</code>. The latter type is also named '''FAT32X''' in order to indicate usage of LBA disk access instead of CHS.<ref name="Caldera_1998_DRFAT32-RM"/><ref name="PowerQuest_1998_PQ4" /><ref name="Livingstone_1998_FAT32X" /><ref name="Duitz_2001_FAQ" /><ref name="Costanzo_1998_FAT32X" /> On such partitions, CHS-related geometry entries, namely the [[MBR partition entry|CHS sector address]]es in the MBR as well as the number of [[BPB sectors per track|sectors per track]] and the [[BPB number of heads|number of heads]] in the EBPB record, may contain no or misleading values and should not be used.<ref name="PowerQuest_1998_FAT32X" /><ref name="Duitz_2001_FAQ" /><ref name="Costanzo_1998_FAT32X" />