SFU is a Unix environment designed to run on top of the Windows kernel. It includes hundreds of Unix utilities, scripting shells and other Unix services.
Microsoft has decided to nix any future, out-of-band releases of SFU, Microsoft officials confirmed earlier this week.
Until recently, Microsoft had been expected to release a "Services for Unix Next" version, which company officials had been hoping to ship in calendar 2005.
This release, the follow-on to the currently shipping SFU 3.5 product, was set to deliver support for botoh x64- and Itanium-based hardware.
Microsoft will continue to support SFU 3.5 until 2011, and to offer extended support for the product until 2014, however.
"There will be no additional releases of SFU," said Samm DiStasio, director of product management with Microsofts Windows Server division. "Customer feedback to us was that they wanted tighter integration of this sort of functionality with the operating system.
"Having Unix interoperability functionality integrated in to the OS (operating system) helps customers to programmatically access Windows and Unix resources at the same time, which is super important and something that couldnt be done with the previous architecture."
"It needs to be part of OS development to ensure it works this way," DiStasio continued. "Customers can use APIs (application programming interfaces) from both worlds, and continue to mature/evolve their apps. In R2, this functionality has been re-architected and in some cases completely re-designed in such a way that it will improve customer experience and integration."
Editors Note: This story was updated to include Microsoft comments on Thursday.