Open source software is becoming a hugely useful resource. A number of projects indicate there's an astounding amount of technology being developed. No matter how much effort is put into developing services and technologies for proprietary operating systems, over the next few years open source development looks set to provide a bigger foundation for richer and more sophisticated operating-system platforms than anything any vendor in the commercial market can achieve.

For example, the latest release of Knoppix 3.8.1 includes UnionFS, a stackable unification file system that merges the updated contents of multiple directories but keeps their original physical content separated.

The UnionFS Web site describes the system as "useful for unified source tree management, merged contents of split CD-ROM, merged separate software package directories, data grids and more. UnionFS allows for any mix of read-only and read-write branches, as well as insertion and deletion of branches anywhere in the fan-out. To maintain Unix semantics, UnionFS handles elimination of duplicates, partial-error conditions and more."

The Knoppix implementation of UnionFS merges the Knoppix RAMdisk with the read-only file system on the boot CD so you can modify any read-only file as if it was writeable.

UnionFS is part of a project called the File System Translator, or FiST . The goal is to address the problem of file system development, a critical (as well as time consuming and expensive) area of operating-system engineering. The FiST site notes: "Even small changes to existing file systems require deep understanding of kernel internals, making the barrier to entry for new developers high. Moreover, porting file system code from one operating system to another is almost as difficult as the first port."

FiST, developed by Erez Zadok and Jason Nieh in the computer science department at Columbia University, "combines two methods to solve the above problems in a novel way: a set of stackable file system templates for each operating system, and a high-level language that can describe stackable file systems in a cross-platform portable fashion."

The idea is that with FiST, a stackable file system would need to be described only once. Then FiST's code-generation tool would compile one system description into loadable kernel modules for different operating systems (currently Solaris, Linux and FreeBSD are supported).

The project claims that with FiST, "code size and development time are reduced significantly, while imposing a small performance overhead of only one to two per cent. These benefits are achieved, as well as portability, without changing existing operating systems or file system."

This is exciting stuff. And while we're talking about Knoppix, we also should mention another interesting Linux distribution, which was conceived of as "the premier distribution for a [small office/home office] that [wants] to create or has an existing Internet business." Yes Linux is intended to be secure and easy to use, and a completely integrated distribution.

Talking of usability, we just received Xandros Desktop, arguably the best attempt, so far, at a truly user-friendly Linux, achieving what one reviewer, Robert Storey, describes as "putting a point-and-click interface on the untamed beast -- think of it as Debian with pizazz".

Storey appears to have been very impressed with the product from the start of his review: "There is not a whole lot to say about the installation, except that Aunt Tilly could do it with her eyes closed (unless she's dead). Xandros boasts superb hardware detection, so unless you've accidentally mistaken a Macintosh for a PC, the install procedure should go smoothly."

Robert said, "There is a running joke that you can install Xandros on a Windows user's hard drive, and he or she won't even notice. That, of course, is an exaggeration -- surely our hypothetical Windows user would wonder what ever happened to Solitaire." This is encouraging, as the goal of a workable non-Windows desktop appears to be getting nearer.