Microsoft security head Ben Fathi is moving into a new job within the software giant after just seven months.

The Security Technology Unit Fathi runs is being absorbed into the company Trustworthy Computing team, led by Scott Charney. Fathi will now act as head of development for the core components of Windows.

The changes are part of a wider re-organisation. Microsoft has changed its top-level Core Operating Systems Division team, and created new groups within it, each focused on a different aspect of the operating system. Plain-speaking Fathi had replaced Mike Nash, who had been the public face of Microsoft's efforts to secure Windows.

Microsoft has improved its reputation for security in recent times, but over the last few months there has been a spike in the number of reported vulnerabilities in its software and the total number of patches issued by the company. On Tuesday, the company issued patches for 26 bugs in its software, the largest single-day patch release.

By merging the Security Technology and Trustworthy Computing units, Microsoft brings together two groups with very similar purposes.

Fathi's unit had been charged with leading "Microsoft's efforts to provide customers with a more secure platform". The Trustworthy Computing team, on the other hand, will "promote a safe, private and reliable computing experience for everyone."

The new Trustworthy Computing team will be one of five units within the re-organised division, which is headed up by Jon DeVaan, senior vice president of engineering strategy. DeVaan reports to Kevin Johnson, who along with Jim Allchin is co-president with the platform and services division.

The changes will take effect when Microsoft finally releases Vista to hardware manufacturers - expected by the end of the year.