View source for Documentation/Maemo 5 Developer Guide/Packaging, Deploying and Distributing/Installing under opt and MyDocs

The N900 has about 100 MB of free space in the root file system partition. This is not very much and would fill up quite quickly when installing additional applications. As a workaround, the <code>/opt</code> directory has been linked to a different partition with more space (about 1 GB) and <code>/home/user/MyDocs</code> is also available in certain cases, with even more space (about 25 GB). Developers are encouraged to make good use of them, specially for applications requiring more than 500 KB, including dependencies.

== /opt as a good alternative ==

The <code>/opt</code> directory is on an ext3 partition that is permanently mounted. Users cannot mess with it by accident. Of course, not everything needs to be moved to <code>/opt</code>: configuration files are best left in <code>/etc</code>, for example, and there is no point in moving small files like the various <code>*.desktop</code> and <code>*.service</code> files (except for the fact that automake's "<code>configure --prefix=/opt</code>" moves them there whether you want to or not). 

The <code>maemo-optify</code> tool helps developers to prepare Debian packages that use <code>/opt</code>. This tool moves selected files inside the package to locations under <code>/opt</code>, and will symbolically link from the original location to the new place of the file. It is available on [http://gitorious.org/maemo-af/maemo-optify gitorious] as well as in [http://maemo.org/packages/view/maemo-optify/ Extras-devel].

The [[Uploading_to_Extras-devel#Autobuilder_special_considerations|Autobuilder]] supports automatic optification of submitted packages via <code>maemo-optify</code>. It is triggered by the file "<code>debian/optify</code>", as described in the [http://gitorious.org/maemo-af/maemo-optify/blobs/master/README README].

== Considering /home/user/MyDocs ==

The <code>/home/user/MyDocs</code> directory is another candidate for large collections of data files included in applications such as game graphics or maps. Using <code>/opt</code> is mostly transparent to package maintainers and end-users, but <code>/home/user/MyDocs</code> needs more careful consideration.

The <code>/home/user/MyDocs</code> partition uses VFAT as its filesystem (which has some limitations compared to ext3) and it is removable: it will be unmounted and exported over USB when the user plugs in the cable. Also, <code>/home/user/MyDocs</code> is visible in the File manager. This all means:

* Be aware that VFAT is not really a POSIX filesystem. Things like symbolic links, permission bits, and so on, will not work as nicely as they do on a real POSIX filesystem.
* Be prepared that your files are not there at all while the partition is unmounted. Do not prevent the partition from being unmounted because you keep some of the files open.
* User might see your files, can get confused and try to delete or rename them.

In summary, you cannot really put programs, libraries or theme graphics into <code>/home/user/MyDocs</code>. Instead, use <code>/opt</code> for these.

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