Microsoft has revealed that it has been quietly working on a version of Windows Server which will run on ARM architecture systems, ending the company's long reliance on x86 architecture chips from Intel and AMD.

Speaking at the Open Compute Project Summit 2017 late last night, Microsoft announced partnerships with ARM licensees Qualcomm and Cavium, among unnamed others, to build ARMv8 (ARM64) servers running Windows Server as part of the company's Project Olympus programme. To do so, the company explained, it has built a version of its Windows Server platform capable of running on the ARM architecture - but, it stresses, the resulting build is earmarked for internal use only.

'We've ported a version of Windows Server, for our internal use only, to run on ARM architecture. We have ported language runtime systems and middleware components, and we have ported and evaluated applications, often running these workloads side-by-side with production workloads,' explained Microsoft Azure engineer Leendert van Doorn in a blog post following the company's presentation at the Summit. 'We feel ARM servers represent a real opportunity and some Microsoft cloud services already have future deployment plans on ARM servers. We are working with ARM Limited on design specifications and server standard requirements and we are committed to collaborate with the community on open standards to advance ARM64 servers for cloud services applications.'

While continuously stressing that the ARM-compatible Windows Server build was an internal project only with no projected public availability, Microsoft nevertheless proved keen to demonstrate what it had created. Attendees at the Summit were treated to Windows Server running on two ARM servers: one based around Qualcomm's 10nm 48-core Centriq 2400 processors, and the other based on Cavium's ThunderX2 ARMv8-A processors. Both motherboard designs have been released to the Open Compute Project, founded by Facebook in an effort to create royalty-free cross-vendor industry standards for the data centre, by their respective creators under Microsoft's Project Olympus banner.

Microsoft has not yet formally confirmed nor denied any plans to release Windows Server for ARM publicly, even as it works with Qualcomm to build an ARM-compatible version of its desktop Windows 10 operating system supported by background emulation of the x86 instruction set architecture.