Editing 8.3 filename (section)

==Directory table==
{{Main|FAT directory table}}
A directory table is a special type of file that represents a directory. Each file or directory stored within it is represented by a 32-byte entry in the table. Each entry records the name, extension, attributes ([[archive bit|archive]], directory, hidden, read-only, system and volume), the date and time of creation, the address of the first cluster of the file/directory's data and finally the size of the file/directory.

Legal characters for DOS filenames include the following:
* Uppercase letters {{code|A}}–{{code|Z}}
* Numbers {{code|0}}–{{code|9}}
* Space (though trailing spaces in either the base name or the extension are considered to be padding and not a part of the filename, also filenames with spaces in them must be enclosed in quotes to be used on a DOS command line, and if the DOS command is built programmatically, the filename must be enclosed in double double-quotes ({{code|""}}...{{code|""}}) when viewed as a variable within the program building the DOS command.)
* {{code|!}}, {{code|#}}, {{code|$}}, {{code|%}}, {{code|&}}, {{code|'}}, {{code|(}}, {{code|)}}, {{code|-}}, {{code|@}}, {{code|^}}, {{code|_}}, {{code|`}}, {{code|{}}, {{code|} }}, {{code|~}}
* Values 128–255 (though if [[National Language Support|NLS]] services are active in DOS, some characters interpreted as lowercase are invalid and unavailable)

This excludes the following [[ASCII]] characters:
* {{code|"}}, {{code|*}}, {{code|+}}, {{code|,}}, {{code|/}}, {{code|:}}, {{code|;}}, {{code|<}}, <code>=</code>, {{code|>}}, {{code|?}}, {{code|\}}, {{code|[}}, {{code|]}}, <code>|</code><ref name=AB>{{cite web |last=Andries Brouwer |author-link=Andries Brouwer |title=Directory Entry |website=The FAT filesystem |date=2007-12-26 |url=http://www.win.tue.nl/~aeb/linux/fs/fat/fat-1.html#ss1.4 |access-date=2013-07-30}}</ref><br/>MS-DOS has no shell [[escape character#Bourne shell|escape character]]
* {{code|.}} ({{unichar|002e|full stop}}) within name and extension fields, except in {{code|.}} and {{code|..}} entries (see below)
* Lowercase letters {{code|a}}–{{code|z}}, stored as {{code|A}}–{{code|Z}} on FAT12/FAT16
* Control characters 0–31
* Value 127 ([[delete character|DEL]]) {{Dubious|date=March 2009}}

The DOS filenames are in the [[code page|OEM character set]].
Code 0xE5 as the first byte (see below) causes issues when [[extended ASCII|extra-ASCII characters]] are used.

Directory entries, both in the Root Directory Region and in subdirectories, are of the following format:

{{Further|FAT directory entry}}
{| class="wikitable"
!width="5%"|Byte Offset
!width="5%"|Length
!width="40%"|Description
|-
|align="right"|0x00
|align="right"|8
|DOS filename (padded with spaces)

The first byte can have the following special values:
{| class="wikitable"
|0x00
|Entry is available and no subsequent entry is in use
|-
|0x05
|Initial character is actually 0xE5
|-
|0x2E
|''Dot entry'': either {{code|.}} or {{code|..}}
|-
|0xE5
|Entry has been previously erased. File [[undelete]] utilities must replace this character with a regular character as part of the undeletion process.
|}
|-
|align="right"|0x08
|align="right"|3
|DOS file extension (padded with spaces, may be empty)
|-
|align="right"|0x0b
|align="right"|1
|File Attributes
The first byte can have the following special values:
{| class="wikitable"
!width="5%"|Bit
!width="5%"|Mask
!width="40%"|Description
|-
|0
|0x01
|Read Only
|-
|1
|0x02
|Hidden
|-
|2
|0x04
|System
|-
|3
|0x08
|Volume Label
|-
|4
|0x10
|Subdirectory
|-
|5
|0x20
|[[Archive bit|Archive]]
|-
|6
|0x40
|Device (internal use only, never found on disk)
|-
|7
|0x80
|Unused
|}
An attribute value of 0x0F is used to designate a long filename entry.
|-
|align="right"|0x0c
|align="right"|1
|Reserved; two bits are used by NT and later versions to encode case information
|-
|align="right"|0x0d
|align="right"|1
|Create time, fine resolution: 10&nbsp;[[millisecond|ms]] units, values from 0 to 199.
|-
|align="right"|0x0e
|align="right"|2
|Create time. The hour, minute and second are encoded according to the following bitmap:
{| class="wikitable"
!width="5%"|Bits
!width="40%"|Description
|-
|15–11
|Hours (0–23)
|-
|10–5
|Minutes (0–59)
|-
|4–0
|Seconds/2 (0–29)
|}
Note that the ''seconds'' is recorded only to a 2&nbsp;[[second]] resolution. Finer resolution for file creation is found at offset 0x0d.
|-
|align="right"|0x10
|align="right"|2
|Create date. The year, month, and day are encoded according to the following bitmap:
{| class="wikitable"
!width="5%"|Bits
!width="40%"|Description
|-
|15–9
|Year (0 = 1980, 127 = 2107)
|-
|8–5
|Month (1 = January, 12 = December)
|-
|4–0
|Day (1–31)
|}
|-
|align="right"|0x12
|align="right"|2
|Last access date; see offset 0x10 for description.
|-
|align="right"|0x14
|align="right"|2
|EA-Index (used by [[OS/2]] and NT) in FAT12 and FAT16, High 2 bytes of first cluster number in FAT32
|-
|align="right"|0x16
|align="right"|2
|Last modified time; see offset 0x0e for description.
|-
|align="right"|0x18
|align="right"|2
|Last modified date; see offset 0x10 for description.
|-
|align="right"|0x1a
|align="right"|2
|First cluster in FAT12 and FAT16. Low 2 bytes of first cluster in FAT32.
|-
|align="right"|0x1c
|align="right"|4
|File size
|}