Cyber Dimensions....

I always wanted to find the precise meaning of the acronyms Microsoft uses to refer to the stage of a product in the software release life cycle. I found the most comprehensive explanation on mvark 's blog and copied it verbatim here for future reference.

Community Technology Preview/CTP

CTP stands for Community Technology Preview. It's generally an incomplete preview of a new technology in progress. These usually come out before beta and are a way to gather feedback from the community during the development of a product. This is similar to an Alpha release per Jeff’s hierarchy, except that at Microsoft, we generally do put CTPs in a public location.

RC's are pretty much like less buggy BETA releases. These are candidates to become the actual release and there is a very small chance of adding new features between the RC and the RTM. Any changes from an RC to an RTM are usually just bug fixes.

RTM stands for "Released to Manufacturing" and is a throwback to the days when software was mostly released as CDs. When a project went "Gold", it was released to manufacturing who then burned a bunch of CDs and packaged them up to be put on store shelves. True, this still goes on today believe it or not, but this mode of delivery is on the decline for certain types of software.

RTW is a related term that stands for "Released to Web" which is more descriptive of how software is actually shipped these days. For example, while we like to use the term RTM internally out of habit, ASP.NET MVC will actually be RTW.

A Fully Supported Out-of-Band release is a release that is not part of the Framework (i.e. it's not included in an installation of the .NET Framework), but is fully supported as if it were. For example, you can call up PSS (Microsoft's Tech Support) for support on a fully supported OOB release.

One example of this was “Atlas” which later became Microsoft Ajax and was rolled into ASP.NET 3.5. ASP.NET MVC 1.0 will be an example of an OOB release.

A Service Pack (or SP) is simply an RTM (or RTW) release of fixes and/or improvements to some software.