Linux could soon threaten the dominance of Unix in the enterprise thanks to the inclusion of features designed to make the operating system (OS) highly available.

One of the most anticipated Linux developments is the inclusion of journaling file systems in the OS kernel that will take it into the realms of enterprise computing. The feature, called Ext3, will be included in the advanced server version of Red Hat 7.2.

The idea behind journaling file systems is to keep track of modifications to the file systems instead of the system's current content. This feature reduces the complexity of a file system check and could help Linux achieve the high availability taken for granted in Unix.

Journaling file systems are safer than conventional file systems as changes applied to the disk's content are kept in a separate log file. They either commit a change or roll back in a transactional manner, much like a relational database.

However, one problem with journaling file systems is that they easily become fragmented. Due to the nature of its allocation file system, journaling soon ends up with blocks scattered all over the disk. This fragmentation is also true for the Ext2 file systems installed by default on every Linux distribution.

Scott Harrison, director of Red Hat, said: "There are certain applications where a journaling file system is essential. It is the one major thing that has been lacking."

Red Hat may not be the first to have a high-performance file system included in its Linux distribution, but Harrison said his company preferred to ensure that the technology it released was "stable".

Currently, Red Hat is helping financial giant Morgan Stanley to move from a Sun Microsystems architecture to an Intel/Linux one. Harrison said Morgan Stanley was "delighted" as it was looking at "substantial savings". "It will do the same thing but at a cheaper price," he added.

But Stacey Quandt, an analyst at Giga Information Group, advised Red Hat users to wait six months for the release of the advanced server version of Red Hat 7.2 to take advantage of the high availability it offered.

She said that in the same week as Red Hat released 7.2, competitors SuSE and MandrakeSoft launched new versions of their Linux distributions.

"For this reason, it is important to keep in mind that not all distributions are equivalent, and that they will vary depending on multiple factors," she said. "Enterprise customers in particular should examine their needs closely and select a Linux distribution that not only provides Linux expertise but technology leadership."