A month ago, Microsoft announced Windows Phone 7 Series at Mobile World Congress in Barcelona. Since its announcement, the newly-rebooted platform has been polished to a state where it's now ready for developers to take charge and start making applications. Almost everything we've suspected has turned out to be true; Phone 7 Series will heavily make use of cloud services such as Xbox Live, and enable huge amounts of code re-use for game and software development with XNA and Silverlight. Microsoft has learned from the success of other platforms how important ease of application development is to platform success, and at MIX10, the emphasis is entirely on developers. Or rather, "Phone Developers" as Steve Ballmer rather humorously suggested:

Phone Developers are Critical

Additional platform details have been announced, including disclosure about both the development framework, tools, and probably most importantly the app marketplace structure for Phone 7 Series. Development will happen atop Microsoft Silverlight 3.0 and Microsoft XNA platforms, leveraging tools like Visual Studio 2010 for Windows Phone, Expression Blend 4 for Windows Phone, and XNA Game Studio 4.0 for Windows Phone. As we suspected earlier, these two frameworks (Silverlight and XNA) lie at the core of Phone 7 Series. Microsoft has been adamant that both Silverlight and XNA developed applications are fully hardware accelerated, and while there's still lag in some applications, the software they've shown thus far is clearly better optimized than it was at MWC.

Microsoft is wasting no time giving developers already familiar with XNA and Silverlight the tools necessary to immediately start building software. The SDK is available and ready, complete with an emulator and support for testing on hardware as soon as it starts shipping. All three of the development tools (Expression Blend, XNA Game Studio, and Visual Studio) are being made available immediately for free at http://developer.windowsphone.com/ . For all intents and purposes, software development for the platform begins now.

Microsoft is taking a two-route approach to application development. They're hoping that the vast majority of productivity, office, and otherwise non-gaming applications will be developed in Visual Studio 2010 or Expression Blend 4 and run atop Phone 7's Silverlight framework. The entire Silverlight 3.0 platform is included and running atop hardware, including a small handful of Silverlight 4.0 features.

A different subset of gaming applications or programs that leverage 3D or require "twitchy response" (like FPS titles), however, will run atop XNA. Once a developer chooses to develop software in one of the two camps, it sticks there for its development cycle. With time, Microsoft plans to bring down these barriers between XNA and Silverlight, but launch this upcoming holiday 2010 is slated to employ this two-camp mode.

This strongly parallels the route that Palm is taking with WebOS, using a basic SDK for most applications, and a "Plug-In Development Kit" (PDK) that allows closer to metal code to run for applications that require better performance and leverage 3D strongly. This model is an interesting balance between both trains of thought; beginning developers looking to make simple applications fast can easily develop with tools like Expression Blend 4. Programmers looking for a closer to metal framework or porting existing Xbox 360 and PC games can choose to use XNA Game Studio.

Probably most interesting, however, is just how much of the code can be shared between PC, Xbox 360, and Windows Phone 7 Series platforms. Microsoft claims 90% or more is more than possible. They demonstrated a title designed in XNA Game Studio 4.0 developed in just 3 weeks called The Harvest which runs almost identically on all three platforms. You can see the game in action for yourself:

I had some concerns about the performance of The Harvest demo and asked a number of Microsoft Game Platform Strategists and XNA tools developers some questions. Although the game clearly stuttered in a few points and had a somewhat variable FPS at times, I'm told that this is not representative from a performance standpoint; obviously this isn't a shipping game. For one, the demo uses the same artwork and textures as both the desktop PC and Xbox 360 versions. For two, the entire demo was developed in just under 3 weeks. Third, I'm told that that the display link (Joe Belifore used a USB link for presenting the display during the keynote) might also be a culprit. Either way, it's reasonable to expect performance to improve drastically.

Microsoft's App Store... Er... Marketplace

Phone 7's Application Marketplace will be the only way to install and get software on the device. Yes, it's that cut and dry. This is definitely a partial letdown for the platform's openness to some extent, mirroring a very apple-esque distribution model and store. At the same time, it's a simplifying move that guarantees common paths to installation. All the same Apple App Store highlights exist here, including one-time credit card information entry and organization. However, one thing Marketplace has that App Store doesn't is complete support for trial software. It's as easy as calling a function called isTrial().

Perhaps the most interesting issues raised were from developers focused on software for corporate employees; without another installation path, anyone could install privileged software. Until a framework exists for them to either have an access token, or an alternate install method, they're out of luck. I'm told Microsoft has taken this feedback seriously and plans to eventually make that happen.

There will be a submission process for applications to be approved and entered in the marketplace, though these details will likely come today or tomorrow (so stay tuned!). What we do know is that there are three specific tests for application approval: business related policies, technical related policies, and (perhaps most controversially) content related policies. Microsoft representative Charlie Kindel repeatedly emphasized that the "approval process will be completely open and [developers will] know what's going on at each step." Again, we fully expect these to be fleshed out during the remainder of MIX10.

Application Submission Workflow

All the rest of what you'd expect from an application marketplace is here, including updates and support for free applications.

Different Target Audience

I asked some of the XNA development team what they thought the biggest takeaway from the entire Phone 7 Series reboot should be, and the response was nearly unanimous: It represents a completely different target demographic focus; consumers.

Microsoft is learning from its experience with Windows Mobile by designing the phone entirely for end users and ordinary consumers; not strictly businesspeople. This target persona has been nicknamed a "Life Maximizer," and it represents the end-user the entire design, from UI to hardware, is being designed around.

Joe Belifore, VP of Phone Development, was forthcoming about both the demographic being targeted in previous Windows Mobile releases, and the tensions inherent in the development cycle for previous Windows Mobile devices. Previously, mobile operators would approach OEMs with a rough list of specifications for hardware they perceived would fill a need a gap in their lineup. The OEMs and mobile operators would work together with an existing reference design, fleshing out a device with potentially different dialers, interfaces, and end user experiences. It's a fair argument that much of the experience fragmentation that this resulted in ultimately was both Windows Mobile's biggest strength, and biggest weakness.

As we noted earlier, Phone 7 Series intends to change all of that by mandating a consistent message to end users. Part of that is also manifested in the hardware mandated now, which Microsoft has released additional details about:

Standardized Hardware Set

The specification list we heard about earlier has been fleshed out with some additional details which I've added emphasis to.

Hardware requirements are:

• Capacitive Touch
• 4 or more contact points
• Sensors
• A-GPS, Accelerometer, Compass, Light, Proximity
• Camera
• 5 megapixels or more, flash required, camera button required
• Multimedia
• Common detailed specs, Codec Acceleration
• Memory
• 256 MB RAM or more, 8 GB Flash or more
• GPU
• DirectX 9 acceleration
• CPU
• ARMv7 Cortex/Scorpion or better
• Screen
• Two Supported Displays
• 480 x 800 WVGA : Aspect Ratio 3:5
  
• 320 x 480 HVGA : Aspect Ratio 2:3

Note that Microsoft is now officially supporting two display resolutions; WVGA and HVGA. These are slightly different aspect ratios, with 320 x 480 HVGA being the standard 3:2 aspect ratio, and 480 x 800 being 5:3 aspect ratio. At the very least, this is something developers can be proactive about and have in mind when building software, as opposed to having the design change after the fact. Hardware launching holiday 2010 will release with 480 x 800 WVGA displays; hardware with 320 x 480 screens will launch later at some unspecified date.

I made note of this to the same XNA team mentioned earlier, who noted that scaling down applications should in theory be easier than scaling up for developers. In addition, they're looking to mitigate the aspect ratio in a number of different ways.

As for the all-important SoC choice, Microsoft is still being very tight-lipped about whether they've picked Snapdragon or one of the many other ARM-licensees' hardware designs. Reps repeatedly declined to discuss what hardware is at the core of current example hardware or whether they'll even mandate a particular chipset. In all likelihood, they'll define minimum requirements and let hardware partners meet or exceed them. Time will tell whether a particular chipset emerges as part of the requirement.

An interesting additional note not part of hardware requirements specifically, but still relevant, is that sync can be performed both tethered through USB to the computer, or over WiFi. Handsets will periodically poll computers over WiFi to see if their primary sync computer is connectible, and if so, sync. Part of the plan is to sync nightly in a manner transparent to the user and transfer photos, notes, and music so that users are never more than a day behind. I had some reservations about how well secured this method is in the long run, but we'll see more as MIX10 continues. Active Sync is dead (to much applause), and the Zune software was announced as the sync platform's successor.

Three Handsets

Thus far, we've seen three handsets from different hardware partners.

The most common of which is the ASUS-built but completely unbranded handset Microsoft is using for most if not all of its demos and hands-ons. I understand this is what Microsoft is distributing to its team internally for development and day to day dogfooding. We've seen this device before numerous times.

There are also now two new devices: First, an LG device with full slide out keyboard. Unfortunately, its battery was dead on-stage and we haven't seen it turned on. This device was first shown during the Engadget show some time ago.

Next is a Samsung handset with no slide out keyboard and a large rear camera.

Nothing further has been said about either of these two new hardware designs, but there are definitely more coming. Curiously absent is Microsoft's traditional major Windows Mobile partner, HTC. We can only assume much more hardware is eventually coming down the pipes.

Demonstration Software

Microsoft emphasized the differences between the Silverlight and XNA framework applications are largely transparent to the user, and showed this off using a number of relatively impressive programs. AP's Mobile News reader, Jackson Fishmarket's Hush Hush Diary, Colorizer, Seesmic, and Graphic.LY were amongst the selected demo applications, with references to many more existing in contextual menus within hubs.

But perhaps the most intriguing and potentially killer application for the handset was Netflix. Since Netflix already heavily relies on Silverlight for streaming media delivery, it's an ideal showcase for Phone 7 Series. Instant playback worked flawlessly. If carriers don't explode at the notion of users streaming the Netflix catalog over already close-to-saturation 3G networks, this alone could be a potentially killer application.

Final Words

Microsoft has answered many of the questions lingering after Windows Phone 7 Series' announcement at Mobile World Congress, however much more remains to be covered at MIX10. Stay tuned!