iloog is a Gentoo-based live CD targeted mainly at students and scientists. It features UnionFS filesystem support that enables you to write everywhere on the LiveCD and install extra packages, a graphical X environment through the Fluxbox window manager, many programming editors and IDEs, and a plethora of scientific applications, including Octave, Namd, Merlin, and full (La)TeX support.
File exchange Protocol can be used to store and retrieve files in a remote repository server using HTTP. It can access a remote server using HTTP requests with authentication to protect the access to the remote files. The class can perform requests to create, write, read, and delete remote files. It can also create, list, and delete directories. It implements a stream wrapper interface to make it possible to access the remote files with PHP functions like fopen('fep://...') and other PHP file and directory manipulation functions. You can also apply a Stream Wrapper that allows you to mount a remote filesystem.
Embedded File System (EFS) is a C++ library that allows you to create virtual file system in a single file. It can be useful when you need to create really big number of small files, as it is still fast even when you have millions of files. An encryption layer could be easily added for security.
Magma is an experimental network filesystem for Linux and BSD kernels based on a distributed hash table. Each object stored is called a "flare" and is managed using its SHA1 hash key. Flares can be moved as opaque objects from node to node and requests can be proxied through the network transparently to the user. Its goals are scalability, redundancy, data availability, compliance with POSIX, and basic encryption on the user side.
RheaVFS allows you to turn an archive into a virtual directory, so all files in the archive can be accessed as if they were in the virtual directory. This works transparently for all programs without any need to modify them. Currently there's read/write support for zip, tar.bz2/gz and gpg encrypted files.
Tagsistant is a semantic filesystem for Linux and BSD kernels. It uses directories as tags and allows file tagging by simply putting files inside desired tag directories. The path you are walking by is your query, e.g. tagsistant/tag1/AND/tag2/OR/tag3/AND/tag2/. Being a low level interface, a filesystem can be instantly used by shell users, file managers, or CGI. A plug-in architecture is under development to add autotagging functionality for common files like .mp3, .ogg, .jpeg, .html, and .xml. A transparent ontology engine is also under development to allow users create a relationship schema between directories.
Einarc is a unified storage RAID command line interface and an API that provides management for various hardware/software RAID devices, uniting them all in a single paradigm. Einarc works as a translator that makes it possible for a user to control all these devices using simple terms like "physical disc", "logical disc", "adapter", etc., while transparently converting these requests to proprietary RAID paradigms.
Debian packaging utilities for Truecrypt source helps to get Truecrypt running with a minimum of effort under Debian-based Linux systems (Debian and Ubuntu are officially supported). Truecrypt is an open source disk encryption software which uses a concept of containers to store encrypted data. The containers (or volumes) can be read transparently under Linux and Windows. The utilities create installable *.deb packages from the sources and those debs can be used in turn to install the encryption software.