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-USING VFAT
-----------------------------------------------------------------------
-To use the vfat filesystem, use the filesystem type 'vfat'. i.e.
- mount -t vfat /dev/fd0 /mnt
-
-No special partition formatter is required. mkdosfs will work fine
-if you want to format from within Linux.
-
-VFAT MOUNT OPTIONS
-----------------------------------------------------------------------
-uid=### -- Set the owner of all files on this filesystem.
- The default is the uid of current process.
-
-gid=### -- Set the group of all files on this filesystem.
- The default is the gid of current process.
-
-umask=### -- The permission mask (for files and directories, see umask(1)).
- The default is the umask of current process.
-
-dmask=### -- The permission mask for the directory.
- The default is the umask of current process.
-
-fmask=### -- The permission mask for files.
- The default is the umask of current process.
-
-allow_utime=### -- This option controls the permission check of mtime/atime.
-
- 20 - If current process is in group of file's group ID,
- you can change timestamp.
- 2 - Other users can change timestamp.
-
- The default is set from `dmask' option. (If the directory is
- writable, utime(2) is also allowed. I.e. ~dmask & 022)
-
- Normally utime(2) checks current process is owner of
- the file, or it has CAP_FOWNER capability. But FAT
- filesystem doesn't have uid/gid on disk, so normal
- check is too unflexible. With this option you can
- relax it.
-
-codepage=### -- Sets the codepage number for converting to shortname
- characters on FAT filesystem.
- By default, FAT_DEFAULT_CODEPAGE setting is used.
-
-iocharset=<name> -- Character set to use for converting between the
- encoding is used for user visible filename and 16 bit
- Unicode characters. Long filenames are stored on disk
- in Unicode format, but Unix for the most part doesn't
- know how to deal with Unicode.
- By default, FAT_DEFAULT_IOCHARSET setting is used.
-
- There is also an option of doing UTF-8 translations
- with the utf8 option.
-
- NOTE: "iocharset=utf8" is not recommended. If unsure,
- you should consider the following option instead.
-
-utf8=<bool> -- UTF-8 is the filesystem safe version of Unicode that
- is used by the console. It can be enabled for the
- filesystem with this option. If 'uni_xlate' gets set,
- UTF-8 gets disabled.
-
-uni_xlate=<bool> -- Translate unhandled Unicode characters to special
- escaped sequences. This would let you backup and
- restore filenames that are created with any Unicode
- characters. Until Linux supports Unicode for real,
- this gives you an alternative. Without this option,
- a '?' is used when no translation is possible. The
- escape character is ':' because it is otherwise
- illegal on the vfat filesystem. The escape sequence
- that gets used is ':' and the four digits of hexadecimal
- unicode.
-
-nonumtail=<bool> -- When creating 8.3 aliases, normally the alias will
- end in '~1' or tilde followed by some number. If this
- option is set, then if the filename is
- "longfilename.txt" and "longfile.txt" does not
- currently exist in the directory, 'longfile.txt' will
- be the short alias instead of 'longfi~1.txt'.
-
-usefree -- Use the "free clusters" value stored on FSINFO. It'll
- be used to determine number of free clusters without
- scanning disk. But it's not used by default, because
- recent Windows don't update it correctly in some
- case. If you are sure the "free clusters" on FSINFO is
- correct, by this option you can avoid scanning disk.
-
-quiet -- Stops printing certain warning messages.
-
-check=s|r|n -- Case sensitivity checking setting.
- s: strict, case sensitive
- r: relaxed, case insensitive
- n: normal, default setting, currently case insensitive
-
-nocase -- This was deprecated for vfat. Use shortname=win95 instead.
-
-shortname=lower|win95|winnt|mixed
- -- Shortname display/create setting.
- lower: convert to lowercase for display,
- emulate the Windows 95 rule for create.
- win95: emulate the Windows 95 rule for display/create.
- winnt: emulate the Windows NT rule for display/create.
- mixed: emulate the Windows NT rule for display,
- emulate the Windows 95 rule for create.
- Default setting is `mixed'.
-
-tz=UTC -- Interpret timestamps as UTC rather than local time.
- This option disables the conversion of timestamps
- between local time (as used by Windows on FAT) and UTC
- (which Linux uses internally). This is particularly
- useful when mounting devices (like digital cameras)
- that are set to UTC in order to avoid the pitfalls of
- local time.
-
-showexec -- If set, the execute permission bits of the file will be
- allowed only if the extension part of the name is .EXE,
- .COM, or .BAT. Not set by default.
-
-debug -- Can be set, but unused by the current implementation.
-
-sys_immutable -- If set, ATTR_SYS attribute on FAT is handled as
- IMMUTABLE flag on Linux. Not set by default.
-
-flush -- If set, the filesystem will try to flush to disk more
- early than normal. Not set by default.
-
-rodir -- FAT has the ATTR_RO (read-only) attribute. On Windows,
- the ATTR_RO of the directory will just be ignored,
- and is used only by applications as a flag (e.g. it's set
- for the customized folder).
-
- If you want to use ATTR_RO as read-only flag even for
- the directory, set this option.
-
-errors=panic|continue|remount-ro
- -- specify FAT behavior on critical errors: panic, continue
- without doing anything or remount the partition in
- read-only mode (default behavior).
-
-<bool>: 0,1,yes,no,true,false
-
-TODO
-----------------------------------------------------------------------
-* Need to get rid of the raw scanning stuff. Instead, always use
- a get next directory entry approach. The only thing left that uses
- raw scanning is the directory renaming code.
-
-
-POSSIBLE PROBLEMS
-----------------------------------------------------------------------
-* vfat_valid_longname does not properly checked reserved names.
-* When a volume name is the same as a directory name in the root
- directory of the filesystem, the directory name sometimes shows
- up as an empty file.
-* autoconv option does not work correctly.
-
-BUG REPORTS
-----------------------------------------------------------------------
-If you have trouble with the VFAT filesystem, mail bug reports to
-chaffee@bmrc.cs.berkeley.edu. Please specify the filename
-and the operation that gave you trouble.
-
-TEST SUITE
-----------------------------------------------------------------------
-If you plan to make any modifications to the vfat filesystem, please
-get the test suite that comes with the vfat distribution at
-
- http://web.archive.org/web/*/http://bmrc.berkeley.edu/
- people/chaffee/vfat.html
-
-This tests quite a few parts of the vfat filesystem and additional
-tests for new features or untested features would be appreciated.
-
-NOTES ON THE STRUCTURE OF THE VFAT FILESYSTEM
-----------------------------------------------------------------------
-(This documentation was provided by Galen C. Hunt <gchunt@cs.rochester.edu>
- and lightly annotated by Gordon Chaffee).
-
-This document presents a very rough, technical overview of my
-knowledge of the extended FAT file system used in Windows NT 3.5 and
-Windows 95. I don't guarantee that any of the following is correct,
-but it appears to be so.
-
-The extended FAT file system is almost identical to the FAT
-file system used in DOS versions up to and including 6.223410239847
-:-). The significant change has been the addition of long file names.
-These names support up to 255 characters including spaces and lower
-case characters as opposed to the traditional 8.3 short names.
-
-Here is the description of the traditional FAT entry in the current
-Windows 95 filesystem:
-
- struct directory { // Short 8.3 names
- unsigned char name[8]; // file name
- unsigned char ext[3]; // file extension
- unsigned char attr; // attribute byte
- unsigned char lcase; // Case for base and extension
- unsigned char ctime_ms; // Creation time, milliseconds
- unsigned char ctime[2]; // Creation time
- unsigned char cdate[2]; // Creation date
- unsigned char adate[2]; // Last access date
- unsigned char reserved[2]; // reserved values (ignored)
- unsigned char time[2]; // time stamp
- unsigned char date[2]; // date stamp
- unsigned char start[2]; // starting cluster number
- unsigned char size[4]; // size of the file
- };
-
-The lcase field specifies if the base and/or the extension of an 8.3
-name should be capitalized. This field does not seem to be used by
-Windows 95 but it is used by Windows NT. The case of filenames is not
-completely compatible from Windows NT to Windows 95. It is not completely
-compatible in the reverse direction, however. Filenames that fit in
-the 8.3 namespace and are written on Windows NT to be lowercase will
-show up as uppercase on Windows 95.
-
-Note that the "start" and "size" values are actually little
-endian integer values. The descriptions of the fields in this
-structure are public knowledge and can be found elsewhere.
-
-With the extended FAT system, Microsoft has inserted extra
-directory entries for any files with extended names. (Any name which
-legally fits within the old 8.3 encoding scheme does not have extra
-entries.) I call these extra entries slots. Basically, a slot is a
-specially formatted directory entry which holds up to 13 characters of
-a file's extended name. Think of slots as additional labeling for the
-directory entry of the file to which they correspond. Microsoft
-prefers to refer to the 8.3 entry for a file as its alias and the
-extended slot directory entries as the file name.
-
-The C structure for a slot directory entry follows:
-
- struct slot { // Up to 13 characters of a long name
- unsigned char id; // sequence number for slot
- unsigned char name0_4[10]; // first 5 characters in name
- unsigned char attr; // attribute byte
- unsigned char reserved; // always 0
- unsigned char alias_checksum; // checksum for 8.3 alias
- unsigned char name5_10[12]; // 6 more characters in name
- unsigned char start[2]; // starting cluster number
- unsigned char name11_12[4]; // last 2 characters in name
- };
-
-If the layout of the slots looks a little odd, it's only
-because of Microsoft's efforts to maintain compatibility with old
-software. The slots must be disguised to prevent old software from
-panicking. To this end, a number of measures are taken:
-
- 1) The attribute byte for a slot directory entry is always set
- to 0x0f. This corresponds to an old directory entry with
- attributes of "hidden", "system", "read-only", and "volume
- label". Most old software will ignore any directory
- entries with the "volume label" bit set. Real volume label
- entries don't have the other three bits set.
-
- 2) The starting cluster is always set to 0, an impossible
- value for a DOS file.
-
-Because the extended FAT system is backward compatible, it is
-possible for old software to modify directory entries. Measures must
-be taken to ensure the validity of slots. An extended FAT system can
-verify that a slot does in fact belong to an 8.3 directory entry by
-the following:
-
- 1) Positioning. Slots for a file always immediately proceed
- their corresponding 8.3 directory entry. In addition, each
- slot has an id which marks its order in the extended file
- name. Here is a very abbreviated view of an 8.3 directory
- entry and its corresponding long name slots for the file
- "My Big File.Extension which is long":
-
- <proceeding files...>
- <slot #3, id = 0x43, characters = "h is long">
- <slot #2, id = 0x02, characters = "xtension whic">
- <slot #1, id = 0x01, characters = "My Big File.E">
- <directory entry, name = "MYBIGFIL.EXT">
-
- Note that the slots are stored from last to first. Slots
- are numbered from 1 to N. The Nth slot is or'ed with 0x40
- to mark it as the last one.
-
- 2) Checksum. Each slot has an "alias_checksum" value. The
- checksum is calculated from the 8.3 name using the
- following algorithm:
-
- for (sum = i = 0; i < 11; i++) {
- sum = (((sum&1)<<7)|((sum&0xfe)>>1)) + name[i]
- }
-
- 3) If there is free space in the final slot, a Unicode NULL (0x0000)
- is stored after the final character. After that, all unused
- characters in the final slot are set to Unicode 0xFFFF.
-
-Finally, note that the extended name is stored in Unicode. Each Unicode
-character takes two bytes.