"Today is a milestone for us in terms of the huge investment and the big innovation going into the next major version of Windows and all the complementary products," Microsoft chairman Bill Gates told delegates at the Windows Hardware Engineering Conference in Seattle.
"We have never had [beta releases] synchronised in this way before. We think it is a great way for us and our customers to see how they all work together as the time comes to roll these things out."
The Beta 2 versions mark the final test phase for Windows Vista and Office 12. Both products are scheduled for release in January 2007 and the betas will be made available for download to the general public.
Windows Longhorn Server Beta 2 is accessible to a group of about 500,000 developers and partners. The software will not be "feature complete" until early next year when Microsoft expects to launch Beta 3.
In the meantime developers should expect to see a number of so-called Community Technology Previews (CTPs).
The CTPs are interim beta releases likely to be focused on specific functionality groups or user cases. Microsoft does not yet know when the first interim CTP code builds will ship.
Molybdenum ditelluride is a two-dimensional material that can be easily stacked into multiple layers to create a memory cell
New light-guiding nanoscale device can control and monitor a nanoparticle trapped in a laser beam with high sensitivity
Optical traps are scientific instruments in which a focused laser beam is used to exert an attractive or repulsive force on a microscopic object to hold it in place
Scientists estimate that the exoplanet has already lost up to 35 per cent of its mass over its lifetime
The observations were made using the Atacama Array in the Chilean desert