Microsoft Corp. has managed to slim down the already slimmed down version of its operating system for virtualized and software container environments.

Windows Server Core, as the operating system is known, does away with nonessential components such as a fancy user interface in order to use less system resources. This lightens the load on the servers it runs on and also adds security benefits because it reduces the attack surface.

Microsoft’s latest update to Windows Server Core, build 17079, is squeezed into a download of just 1.58 gigabytes, which is about a third smaller than the previous version. Once downloaded and unpacked, it’s about 20 percent smaller, taking up 3.61GB of hard drive space.

Weijuan Shi Davis, a program manager at Microsoft, said in a blog post that the Windows Server Core team managed to apply some of the same techniques that were used to reduce the size of its Nano Server images. In addition, the team assessed publicly available images, feedback and forum posts on the GitHub code repository, to see which features could be safely stripped away without removing any essential functionality.

“We looked at all the various roles, features and optional components available in Server Core and broke them down into a few buckets in terms of usage: frequently in containers, rarely in containers, those that we don’t believe are being used and those that are not supported in containers,” Davis said.

Besides making Windows Server Core smaller, the team also added the ability to install Microsoft Message Queuing inside containers, which allows for asynchronous communications between applications on a network.

Microsoft is also making it easier for members of its early access program, Windows Insiders, to test new releases. Windows Server Core can now perform in-place upgrades from build 1709 to the latest version without having to install everything from scratch.

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