Microsoft has announced one of the biggest reorganisations in the company’s history, as it seeks to adapt itself to better meet the challenges of today’s fast-paced IT industry. Existing business units are being swept away to be replaced by four engineering areas comprising OS, Apps, Cloud, and Devices.

The radical restructuring of the software giant was unveiled in an email from Microsoft chief Steve Ballmer to all employees, which has been posted on the firm’s website.

In the email Ballmer said that the changes, “will enable us to execute even better on our strategy to deliver a family of devices and services that best empower people for the activities they value most and the enterprise extensions and services that are most valuable to business.”

To do this, Microsoft is aiming to present itself as “one company, not a collection of divisional strategies”. This strategy is aiming at driving the company forward with a set of shared goals through which its product line-up will be seen holistically rather than seperate areas.

“All parts of the company will share and contribute to the success of core offerings, like Windows, Windows Phone, Xbox, Surface, Office 365 and our EA offer, Bing, Skype, Dynamics, Azure and our servers. All parts of the company will contribute to activating high-value experiences for our customers,” Ballmer said.

To effect this change, the company is being reordered around functions such as engineering, marketing, business development, advanced strategy and research, finance, HR, and legal.

The Engineering function will be split across four engineering teams targeting OS, Apps, Cloud, and Devices, while Dynamics will be kept separate “as it continues to need special focus and represents significant opportunity,” according to Ballmer.

Of these areas, the Operating Systems Engineering Group will be led by Terry Myerson and will encompass all OS work across Microsoft’s mobile devices, PCs, and back-end systems.

The Devices and Studios Engineering Group is being headed by Julie Larson-Green, covering all hardware development from the smallest to the largest devices.

Meanwhile, the Applications and Services Engineering Group led by Qi Lu covers applications and service core technologies across productivity, communication, search and other information categories.

Satya Nadella is heading up the Cloud and Enterprise Engineering Group, developing technologies datacentre and database technologies and other specific tools for enterprise IT scenarios.

The move is a monumental upheaval for Microsoft and its employees, but one that Ballmer said is necessary for the company to move forward and meet the challenges it faces.

“This is a big undertaking. It touches nearly every piece of what we do and how we work. It changes our org structure, the way we collaborate, how we allocate resources, how we best empower our engineers and how we market,” he said.