Cross building Debian Emdebian borrows a technique from OpenEmbedded to handle translations which is already outlined within Debian as "Tdeb" - translation debian packages. The Emdebian implementation of tdebs differs from the proposed tdebs for Debian because Emdebian does not care about manpages in general, let alone translated manpages. Once the 'nodocs' DEB_BUILD_OPTION is supported in debhelper, this will not be an issue as the tdebs can be built for Emdebian without any manpages. Other translated documentation would be omitted under 'nodocs' too. Images containing translated text are relatively few. Therefore, the majority of the Emdebian tdeb implementation can be applicable to Debian. Debian packages collate all available translations into a single package which can easily lead to over 250Mb of unused translation files on a typical installation. i.e. the translations alone could take up four times the amount of space intended for the entire embedded operating system. One locale, one package, one tdeb em_installtdeb is a new script in emdebian-tools based on debhelper, to create translation packages (tdebs). em_installtdeb is intended to separate out the individual translation files from the current Debian packages into packages without any translation files and a series of tdeb locale packages, one per translation. Generated packages use the syntax: $package-locale-$languagecode_$version_all.deb. Once a package uses em_installtdeb, translation files should be removed from all packages in the normal build. em_installtdeb runs as a second build (very small, very fast) that simply converts and packages the *.po files into tdebs. A tdeb source package is created (.dsc, tdeb.tar.gz and .changes) alongside the existing build data. The source package can be used by translators to build updated or new tdeb packages. Tdeb .changes files need to be uploaded only to secondary locale repositories instead of the main Debian mirrors and these repositories can have much more relaxed upload policies. Tdeb packages have no dependencies and no packages may depend upon them. Each package now built for Emdebian includes tdeb support so that if the package contains gettext-compliant translations, tdeb packages are created. Emdebian also supports a locale repository with search support. Currently, certain compromises are made to allow tdebs to work without changes to packages like dpkg or reprepro - including the need to make two uploads, one for the main package (without translations) and one for the generated tdeb .changes file including generated tdeb source and all of the tdeb packages. For more information on em_installtdeb, see the em_instal ltdeb manpage. Emdebian generates a single package for every translation of each Emdebian package, leading to a 70% reduction in installation size but a tenfold increase in the number of binary packages built from each source package. To solve this scalability problem, Emdebian provides a new C/C++ application (langupdate) handling the installation and update of tdeb packages according to the list of supported locales and the list of installed packages. Data cached by langupdate is temporary and is not intended to be stored between runs of langupdate (i.e. it can be stored completely in RAM). The secondary locale repository organises the tdeb packages by locale root, e.g. 'en_GB' is beneath 'en' and 'sr@Latn' beneath 'sr'. Each locale root becomes a single apt source in the locale repository to support fallback from a specific locale to a the more general locale root. In this manner, each device only has to cope with cache data for a fraction of the total number of tdeb packages (roughly 1 part in 30). The tdeb cache itself is temporary so the only effect on the device package data is the small number of locale packages that are actually installed. tdebs have no long description and no dependencies sothe effect on the dpkg lists should be minimal. langupdate queries the secondary apt cache to get a list of all translation packages (tdebs) that match the list of locales supported on the device. This list is then compared with the list of installed binaries. The translation packages that match the installed package are then installed by passing options to apt-get. langupdate uses a temporary file for the sources.list and updates it from the list of supported locales each time langupdate is run, i.e. it combines the effects of 'apt-get update' with 'apt-get upgrade'. tdeb packages have no dependencies so 'dist-upgrade' is not required. langupdate is a native Emdebian package - it may appear in Debian at a later date when Debian supports tdebs. em_installtdeb includes outline support for translator uploads. This is intended to allow translators to add the locale deb-src source to their apt sources lists and use apt-get source $package-locale-$lang to download the tdeb source: the POT file, existing PO files and enough metadata to be able to build a new or updated tdeb package for a specific language using em_installtdeb $lang. The build generates a new (binary-only) .changes file suitable for upload direct to the locale repository. There are issues to be resolved within this support before it can be made widely available, relating to merging the new translations back into the Debian package, but everything related to tdebs in Emdebian should be considered "experimental".