In case you missed it, it's worth noting that Red Hat doesn't give away its Linux software any more. Or at least it doesn't if you're looking for a well supported platform for enterprise applications. In which case you're encouraged to subscribe to Red Hat Enterprise Linux (RHEL), the code for which is updated at a much more considered and manageable pace than Fedora, the freebie implementation aimed at the Linux enthusiast.

With a release cycle measured in years rather than months, new technologies, applications and updates are tried and tested in Fedora first before being added to Red Hat Enterprise, making, in theory at least, for a much more stable platform. Added to which you're guaranteed backwards compatibility, with bundled libraries to support applications compiled for the previous two generations (RHEL 2.1 and 3).

Wide platform support is another plus, with implementations for not just Intel and AMD processors but the IBM Power series and mainframe systems. Moreover, this latest release, based on a 2.6.9 Linux kernel, is fully 64-bit enabled and can be run on Itanium 2, Xeon EM64T and AMD64 processors, with enhancements for both hyper-threading and the latest breed of multi-core processors now as standard.

RHEL 4 also provides support for both SMP and NUMA architectures, along with a new hardware abstraction layer better equipped to deal with plug-and-play devices, and support for ACPI, the Advanced Configuration and Power Interface, version 2.0.

A new block I/O layer further helps improve both performance and scalability, on top of which the journaled Ext3 file system is now better equipped to handle large databases. Plus you get a new version of the Red Hat Logical Volume Manager (LVM2) with support for online growth of file systems to help simplify storage management.

Each of these enhancements has been tried and tested over several iterations of Fedora before being added to RHEL 4. As too has Security Enhanced Linux (SELinux) which allows administrators to define fine-grained security policies right down to the process level rather than have to rely on the traditional, rather cumbersome, user/group approach. SELinux can be specified during the install and is fully integrated with the main bundled applications such as Apache and the BIND DNS server.

The latest Apache and Samba servers, naturally, also come as standard, while in terms of actual deployment, the best word to describe RHEL 4 is 'smooth'. Indeed, the maturity of the product is more than reflected in the slick install routine which gave us no problems at all when loading the software onto a range of different hardware.

The default Gnome desktop is a delight too, with numerous enhancements including automatic detection of network resources and USB devices. Added to which, for desktop deployment, you get a copy of OpenOffice, the Evolution e-mail and calendar tool, and the latest Firefox browser.

Of course it's not completely perfect. For example, it would be nice if management of some of the optional add-ons was integrated into the core O/S tools, as in SuSE and Windows, especially when it comes to SELinux, which can be very difficult to set up if you're not familiar with it.

However, the documentation is excellent, as are the Red Hat automatic update and support services. Moreover, management shouldn't be an issue for most enterprise deployments where this stable and very mature Linux is suitably equipped to win yet more converts.

If it's a mature and stable Linux you want then Red Hat Linux Enterprise 4 more than fits the bill. Fully supported by Red Hat itself and incorporating numerous enhancements that have been fully tested and debugged in the free Fedora implementation, it's faster, more scalable and secure than ever before. A proper enterprise Linux from the market leader.