Build 2015 is where the Microsoft truly begins the work of selling Windows 10, starting with developers.
"This is a really important Build for Microsoft, probably the most important developer conference it has ever done. The company is on the brink of launching a new wave of operating system technologies that will affect almost everything it delivers over the next few years," said Al Hilwa, IDC analyst who covers enterprise development, by e-mail.
Held this week in San Francisco, with the first keynote kicking off Wednesday morning, Build 2015 also promises to provide developers with more information about how to prepare their applications for the cloud, and may even offer a glimpse into HoloLens, the Windows 10-based virtual reality headset.
"Overall, I expect the developer story for almost all Microsoft products to be moved forward at Build," Hilwa wrote.
Expected to be released midyear, Windows 10 will be the first version of Microsoft's flagship operating system to run across personal and laptop computers, tablets and smart phones.
Revenue from Windows licenses has been declining, so Build is nothing short Microsoft's bid to stay relevant in the post-PC era.
"Build is the first big effort to get developers and hardware makers on board with the product," wrote Rob Enderle, head of the IT analyst firm Enderle Group, in an e-mail. "This is where people will first see some of the surprises in the product that haven't yet been on earlier builds."
With Windows 10, Microsoft is hoping to make development easier by offering a single way to write an application that could run across multiple Windows devices -- smart phones, tablets, laptops and personal computers. Windows 10 will offer a single API (application programming interface) that can be used for all devices running Windows.
The API can address unique capabilities in specific devices such as the GPS capabilities of smartphones. Or developers could just use the subset of APIs that apply for all the devices running Windows, allowing developers to maintain a single code base for multiple form factors.
Microsoft has always considered developers integral to its success, but the work Build will need to do to sell the programming community on the power of Windows 10 will be considerable.
"It needs to convince developers that it has great tools that will make their jobs easier and give them a greater reach with their products. And it needs to show that Microsoft is 'cool' and worth investing some time and effort in," wrote Steve Kleynhans, vice president, for the mobile and client computing group of the Gartner IT analyst company.
Microsoft will also need to woo developers into trying new Windows features like the Hello biometric sign-on tool, and the back-end Passport authentication software.
Perhaps most importantly, "Microsoft needs to show how Windows still fits in the overall vision of Microsoft which is increasingly cloud-centric and device agnostic," Kleynhans said.
At the same time, Microsoft will also have to extol the virtues of its Azure cloud service. Microsoft will likely provide more details on how Azure is addressing the growing use of containers and hyper-scale computing, noted Dave Bartoletti, a Forrester analyst who covers cloud computing, by e-mail.
The recent wave of popularity in the Docker container technology comes in part because it allows organizations to re-architect their complex enterprise applications as a collection of modular micro-services, an approach that promises to help organizations modify and update these applications more quickly.
Another recent wrinkle in IT has been hyper-scale computing, in which the cloud service itself takes care of scaling up an application should it become too heavily used to run on a single set of virtual servers.
Microsoft has recently released Azure updates to address both these technology areas, and may reveal additional features this year at Build, Bartoletti said.
"We're looking forward to orchestration services, new mobile development tools, and additional support for various container technologies -- all designed to help position Azure at the center of enterprises' digital business strategies," Bartoletti said.
Every good technology conference has some futuristic buzz-worthy technology to prod attendees into thinking about the future of computing. This year that technology looks to be HoloLens, a Windows-based virtual reality headset that Microsoft unveiled in January. The company has promised that the HoloLens will run on Windows 10, so developers will be eager to see how these high-tech glasses work.