Stories by: Tom Henderson and Brendan Allen

There's "the cloud" and then there's Windows Azure.

Ubuntu 11.04 (nicknamed Natty Narwhal) marks a decided change in direction for the Linux-based operating system. The biggest change is that Canonical, the organizer of Ubuntu, is replacing the Gnome/KDE desktop environment with a new user interface called Unity.

Nimbula's founders developed the Amazon EC2 public cloud system and are now working on Nimbula Director, which aims to partition internal cloud resources by authentication, along the lines of how EC2 works.

The potential benefits of public clouds are obvious to most IT execs, but so are the pitfalls -- outages, security concerns, compliance issues, and questions about performance, management, service-level agreements and billing. At this point, it's fair to say that most IT execs are wary of entrusting sensitive data or important applications to the public cloud.

On the surface, Apple's Snow Leopard Server feels like a $US499 maintenance release, but underneath, there's much more - improved performance, more polish and new apps focused on collaboration and content sharing.

Ubuntu Server is a fast, free, no-frills Linux distribution that fills a niche between utilitarian Debian and the GUI-driven and, some would argue, over-featured Novell SUSE and Red Hat Enterprise Linux.

Both hypervisors we tested have requirements for the hardware they can run on and the virtual machines they can support.

When the dust settled in the lab after two long months of testing Microsoft’s Hyper-V and VMware’s ESX in the areas of performance, compatibility, management and security, it all boiled down to two issues: experience and religion.

With the recent release of Microsoft's Hyper-V shaking up the hypervisor market, we decided to conduct a two-part evaluation pitting virtualization vendors against each other on performance as well as on features such as usability, management and migration.