FunionFS is a FUSE driver that supports an Union filesystem.
In essence, an Union filesystem is a way to create a LiveCD Linux such as Knoppix, wherein the support (CDROM) can only be read-only. However, the operating system requires write access to this filesystem. The solution is to overlay (Union) a small read-write filesystem on top of the read-only version. This small filesystem - typically stored in a RAMDISK - contains all the modifications made by the operating system on the CDROM content.
The Union filesystem is an excellent solution for Linux stored in a PROM or a compressed file, such as in CRAMFS.
Regarding updates and enhancements, this release of FunionFS comes with the correction of some bugs. Additionally, there's a pending rewrite of the directory management, which will address some of the issues that occur when overlaying multiple directories.
Overall, FunionFS is a reliable and efficient Union filesystem for your FUSE driver. If you require a method for creating a LiveCD Linux, it's an excellent choice to consider.
Version 0.4.3: N/A