Microsoft has revealed more information on changes to the Vista kernel as part of the release of Service Pack 1, but has denied that the enhancements amount to an "upgrade" or "re-engineering".
In a statement released to ZDNet.co.uk on Wednesday, a Microsoft spokesperson confirmed that enhancements have been made to the Vista kernel, taking the form of an extended set of APIs designed to benefit 64-bit application development.
"The kernel has not been re-engineered. However, some APIs have been introduced through SP1 [Service Pack 1] which help ISVs [independent software vendors] develop software to run on 64-bit PCs (they patch the kernel)," Microsoft stated.
Reports early this week intimated that the Vista kernel had undergone a relatively substantial overhaul that, if confirmed, may have prompted concerns among application providers and end users over possible instability.
However, other reports have claimed that an update to the Vista kernel to coincide with the release of SP1 and to aid integration with Windows Server 2008 has always been on the cards, and that any concerns over possible incompatibility with third-party applications as a result are unfounded.
Third-party software vendors would not comment on the impact of any changes to the Vista kernel with SP1. However, Quocirca analyst Clive Longbottom said that kernel updates are relatively routine and usually go largely unnoticed.
"I suppose that the big worry is that the kernel may behave in a different way and that any external applications that access the kernel directly may no longer work. But, on the whole, it would have to be a very badly behaved application that made calls to the kernel that weren't authorised by Microsoft through its published APIs," said Longbottom.
Commenting directly on rumours of the kernel upgrade, Longbottom added: "It's likely that bringing the Vista kernel in line with the Longhorn kernel in Windows Server 2008 will reduce possible non-compatibility between the two operating systems and ensure that a single code stream can be carried forwards to minimise development team hassles."
The newly extended Vista APIs in SP1 will be available in March alongside Windows Server 2008. SP1 features architectural changes designed to address application compatibility.
Microsoft has claimed Windows Vista SP1 will deliver improvements and enhancements to existing features, but not substantial new operating system features. For example, the service pack is designed to improve the performance of the desktop shell, but it does not provide a new search user interface or a new version of Windows Media Center. According to Microsoft, the goal of Windows Vista SP1 is to address key feedback that the company has received from its customers without regressing application compatibility.
SP1's core features support for emerging technologies such as the new exFAT file system for mobile data storage. It also embraces the upcoming Direct3D 10.1 graphics card and the Unified Extensible Firmware Interface specification.
Focusing on the corporate market, Microsoft has said that there are additional changes in SP1 designed to make it easier to configure, manage and deploy Vista with improved network diagnostics, a more efficient Remote Desktop Protocol and a more configurable disk defragmenter.
To coincide with the SP1 and Windows Server 2008 announcements, Microsoft is making a new selection of tools and training available. These resources have been developed in line with feedback from more than two million beta and evaluation customers. Microsoft is offering free tools to assess an enterprise's current servers and determine which can be upgraded and which will require a "clean install". The company is also operating a "Certified for Windows Server 2008" logo programme, working with original equipment manufacturers (OEMs), independent hardware vendors (IHVs) and independent software vendors (ISVs) in an attempt to maximise compatibility.