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* docs/grub.texi (Internationalisation): New section.

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Vladimir 'phcoder' Serbinenko 2011-12-22 20:55:55 +01:00
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@ -1,3 +1,7 @@
2011-12-22 Vladimir Serbinenko <phcoder@gmail.com>
* docs/grub.texi (Internationalisation): New section.
2011-12-22 Vladimir Serbinenko <phcoder@gmail.com>
* docs/grub.texi (Loopback booting): New section.

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docs/grub.texi
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@ -89,6 +89,7 @@ This edition documents version @value{VERSION}.
* Interface:: The menu and the command-line
* Environment:: GRUB environment variables
* Commands:: The list of available builtin commands
* Internationalisation:: Topics relating to language support
* Security:: Authentication and authorisation
* Supported kernels:: The list of supported kernels
* Troubleshooting:: Error messages produced by GRUB
@ -3893,6 +3894,65 @@ Unset the environment variable @var{envvar}.
This command is not yet implemented for GRUB 2, although it is planned.
@node Internationalisation
@chapter Charset
GRUB uses UTF-8 internally other than in rendering where some GRUB-specific
appropriate representation is used. All text files (including config) are
assumed to be encoded in UTF-8.
@chapter Filesystems
NTFS, JFS, UDF, HFS+, exFAT, long filesnames in FAT, Joliet part of
ISO9660 are treated as UTF-16 as per specification. BFS is read as UTF-8,
again according to specification. BtrFS, cpio, tar, squash4, minix, minix2,
minix3, ROMFS, ReiserFS, XFS, ext2, ext3, ext4, FAT (short names),
ISO9660 (plain and RockRidge), nilfs2, UFS1, UFS2 and ZFS are assumed
to be UTF-8. This might be false on systems configured with legacy charset
but as long as the charset used is superset of ASCII you should be able to
access ASCII-named files. And it's recommended to configure your system to use
UTF-8 to access the filesystem, convmv may help with migration. AFFS and HFS
never use unicode and GRUB assumes them to be in Latin1 and MacRoman
respectively. NTFS, HFS+, FAT and exFAT are case-insensitive however no
attempt is performed at case conversion of international characters so e.g.
a file named lowercase greek alpha is treated as different from the one named
as uppercase alpha. Also similar to POSIX systems GRUB make no attempt at check
of canonical equivalence so a file name u-diaresis is treated as distinct from
u+combining diaresis. This however means that in order to access file on
HFS+ its name must be specified in normalisation form D. On ZFS subvolumes
marked as case insensitive files containing lowercase international characters
are inaccessible.
@chapter Output terminal
Firmware output console ``console'' on ARC and IEEE1275 are limited to ASCII.
BIOS firmware console and VGA text are limited to ASCII and some pseudographics.
None of above mentioned is appropriate for displaying international and any
unsupported character is replaced with question mark except pseudographics
which we attempt to approximate with ASCII. EFI console on the other hand
nominally supports UTF-16 but actual language coverage depends on firmware and
may be very limited. The encoding used on serial can be chosen with
@command{terminfo} as either ASCII, UTF-8 or ``visual UTF-8''. Last one is
against the specification but results in correct rendering of right-to-left
on some readers which don't have own bidi implementation. When using gfxterm
or gfxmenu GRUB itself is responsible for rendering the text. In this case
GRUB is limited by loaded fonts. If fonts contain all required characters
then bidirectional text, cursive variants and combining marks other than
enclosing ones. Ligatures aren't supported though. This should cover
European, Middle Eastern (if you don't mind lack of la-alef ligature in
Arabic) and East Asian scripts. Notable unsupported scripts are Brahmic family
and derived as well as Mongolian and Tifinagh. If you can complete either of
two lists or, better, propose a patch to improve rendering, please contact
developper team.
@chapter Input terminal
Firmware console on BIOS, IEEE1275 and ARC doesn't allow you to enter non-ASCII
characters. EFI specification allows for such but author is unaware of any
actual implementations. Serial input is currently limited for latin1 (unlikely
to change). Own keyboard implementations (at_keyboard and usb_keyboard) can
support any characters but work on one-char-per-keystroke. So no dead keys or
advanced input method. Also there is no keymap change hotkey. In practice it
makes difficult to enter any text using non-Latin alphabet.
@chapter Gettext
GRUB supports being translated. For this you need to have language *.mo files in $prefix/locale, load gettext module and set ``lang'' variable.
@node Security
@chapter Authentication and authorisation