IIS Extensions and servicing

This week, IIS team has released two servicing patches for the following IIS Extensions:

• FTP for IIS 7.0 (KB955136)
• x86: http://www.microsoft.com/downloads/details.aspx?FamilyID=f23f366f-5d1c-4390-934c-d5e9c3057661&DisplayLang=en
• x64: http://www.microsoft.com/downloads/details.aspx?FamilyID=1d4264c7-783a-4381-a65c-39eb148820de&DisplayLang=en 
• WebDAV for IIS 7.0 (KB955137)
• x86: http://www.microsoft.com/downloads/details.aspx?FamilyID=567cb0d6-3e94-4035-a79d-22d1ef307d5e&DisplayLang=en
• x64: http://www.microsoft.com/downloads/details.aspx?FamilyID=31fc62d7-abd0-4ac0-b727-d5ef0a50f8cc&DisplayLang=en

They are the first servicing releases that the IIS team has done for IIS Extensions and I wanted to take this time to explain how we plan on servicing IIS Extensions and highlight some of the key differences between the Windows OS components servicing and IIS Extensions servicing.

• Deployment technology:  I have written a few blogs about CBS (component based servicing).  CBS was first introduced in Windows Vista and for both Windows Vista and Windows Server 2008, CBS is how operating components, including IIS, are serviced.  For IIS Extensions, the deployment technology is MSI (Microsoft Installer) which is the most common way of installing applications on Windows OSes.  An update to a MSI is done via MSP (Microsoft Installer Patch) and the IIS Extension servicing releases are packaged in MSPs.

• Scope and frequency: The servicing Hotfixes (also sometimes referred as QFEs - Quick Fix Engineering) for operating systems are targeted in that one Hotfix addresses one specific bug.  Also, because the scope is small, the turn-around time is relatively quick, depending on the priority and the severity of the bug and the associated SLA (Service Level Agreement).  With IIS Extension servicing, as you may have noticed from the KB articles for FTP and WebDAV, the MSPs may contain one or more bug fixes.  Naturally, the frequency of IIS Extension servicing releases will vary based on the priority and the severity of the bugs and the scope of the release, determined both by the number of bug fixes and the complexities.

• Distribution: Typically, the OS Hotfixes are made available to customers who contact the Microsoft support team.  As noted above, the Hotfixes, by definition, address very specific and targeted problems.  Given this nature, most Hotfixes are not applicable to every user of Windows.  There are exceptions, such as security fixes, and in those situations, we make the bug fixes available to the general public.  For IIS Extension servicing releases, they are made publicly at Microsoft Download Center.