Microsoft Explains Vista Build Numbers
The Microsoft official responsible for releasing Windows Vista builds explained
in an interview published on the Vista Team Weblog this week some of the intricacies
of how the build numbering scheme for Release Candidates works.
In the interview, Sven Hallauer, director of release management for Windows
Vista, said the company currently has parallel build cycles in play for builds
numbered 5400 through 5699 which are reserved for Release Candidates (RC). At
the same time, it also has reserved builds numbered 5700 and above for Release
to Manufacturing (RTM) -- the step following the last RC build and the code
that will ultimately be released to customers.
"So does this mean that MS is working on builds for RC1 and RTM in parallel?
You bet!" says the posting that accompanies the interview online.
"We've done this since XP...basically, it helps us to optimize
the ability to make the code move forward in a very fast way," Hallauer
said. "That's something that we do at the end of every major milestone...that
we basically branch off [to one of the sets of build numbers], and out of the
branch we drive the actual milestone build."
The interview is posted in both .MP3 and Windows Media Audio (.WMA) formats.
The new code branches appear to be yet another indication that Microsoft is
determined to stay on track to release Vista to business customers in November
and release to consumers in January. Earlier this week, the company made 100,000
pre-Release Candidate 1 copies of an interim release build available for
The pre-RC1 builds followed disclosure earlier in August that the company had
started a Release
Candidate "branch" in Vista’s code tree. The company typically
releases from one to three RCs before releasing the final code to manufacturing.
"We've got about 5,000 engineers working on [Vista]...and when
you get close to the end of the milestone...the last five, maybe six weeks,
there comes the point where you say, 'We need to slow down the churn in
order to bring everything together' [and] saying, 'Hey, we can stabilize
this platform at a certain quality bar and then go ship it.'" Counting other
parties, such as product marketing, the total team is more like 8,000, he said
-- a far cry from the early days of MS-DOS and Windows when there were only
small teams working to turn out the code for major products.
The biggest risk, Hallauer said, is in regression testing of any software product,
and the build numbering and branching scheme is a method to help resolve outstanding
fixes. "All the fixes taken into the branch out of which we ship the major
milestones always come back to the main line [of the code tree] so they're
always part of what we ship as the next milestone out."
Right now, of course, the development teams are putting in 50- and 60-hour
weeks. But Release Candidate 1 (aka "RC1") will define how close
the company actually is to Release to Manufacturing, or RTM. And as soon as
RC1 comes out, Hallauer is urging everyone to aggressively begin testing it
right away in order to be sure that any major problems are found and fixed.
"Time is of the essence...we've got a feedback window of about
two or three weeks after RC1 is released where we can really make changes that
are deeper into the product code base...and thereafter we just become very,
very constrained in terms of what we actually can change without resetting the
clock and slipping the release [date]."
In terms of current status, whereas in the early beta stages, testers identified
bugs in the core code, these days most bugs are being found in third-party driver
code, Hallauer said. Although the company has not said yet when RC1 will be
released, many analysts anticipate that it will ship by mid-September.
You can listen to the entire interview here.
Stuart J. Johnston has covered technology, especially Microsoft, since February 1988 for InfoWorld, Computerworld, Information Week, and PC World, as well as for Enterprise Developer, XML & Web Services, and .NET magazines.