Freshmeat: Virtual Filesystem: Building A Linux Filesystem From An Ordinary File

"You can take a disk file, format it as an ext2, ext3, or reiser filesystem, and then mount it, just like a physical drive. It's then possible to read and write files to this newly-mounted device. You can also copy the complete filesystem, since it is just a file, to another computer. If security is an issue, read on. This article will show you how to encrypt the filesystem and mount it with ACL (Access Control Lists), which gives you rights beyond the traditional read (r), write (w), and execute (x) permissions for the three user groups "file", "owner", and "other".

"This is an excellent way to investigate different filesystems without having to reformat a physical drive, which means you avoid the hassle of moving all your data. This method is quick -- very quick compared to preparing a physical device. You can then read and write files to the mounted device, but what is truly great about this technique is that you can explore different filesystems such as reiserfs, ext3, or ext2 without having to purchase an additional physical drive. Since the same file can be mounted on more than one mount point, you can investigate sync rates..."

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Related Stories:

• developerWorks: Preventing Race Conditions(Oct 12, 2004)
• Linux Journal: Filesystem Labeling in SELinux(Oct 08, 2004)
• internetnews.com: Building a Better Filesystem For Linux(Aug 26, 2004)