Windows 8 Developer Preview

Microsoft has been showing off bits and pieces of its next-generation Windows operating system over the last few months, finally releasing a developer preview at its BUILD conference. This preview is intended to give developers the opportunity to work with Windows 8's new Metro-style user interface, and to learn how to create applications for what's a very different Windows. It's pre-beta code, and so can be a little buggy at times, but has many of the features that will appear in the final version.

Described by Microsoft President Steven Sinofsky as "a bold re-imagination of what Windows could be", Windows 8 brings a new touch-friendly user interface to the venerable platform, along with a new development model and new development tools. HTML and JavaScript are first-class citizens, along with Silverlight, which moves away from being a browser plug-in to a new user interface for .NET managed code Windows applications. Windows 8 departs from the familiar desktop model of files and applications to something quite different, designed for touch and for mobile users.

There's also deep cloud integration in the OS, and Microsoft's consumer cloud service Windows Live is a key component of the Windows 8 user experience. Logging on to a Windows 8 machine for the first time, you'll be asked to enter an existing Windows Live ID, or create a new one from scratch. Live handles a lot of Windows 8's connectivity and social media features, bringing in new versions of the Windows Live Essentials software and tying the OS to Microsoft's Live SkyDrive storage platform.

Start Here
Turn on a Windows 8 device, and you'll be presented with a new-look lock screen. You can personalise the backdrop, although you'll need a HD-quality image to make the most of the recommended 1,366-by-768-pixel resolution. A set of glyphs on the lock screen provide a quick overview of device status — network connections, email and calendar information, as well as a large, clear clock.

Windows 8's Metro Start screen is the new Windows shell, relegating the old desktop to simply another application; Live Tiles show information, as well as launching applications

A simple swipe gesture moves you away from the lock screen. Windows 8 supports several different password schemes, with the option of traditional passwords and PINs (using a Windows Live password) or the new Picture Password tool. This lets you use elements of a picture from your library as a key, with three gestures on specific parts of the image unlocking your device.

The heart of Windows 8 is the new Start screen, built using Microsoft's Metro look-and-feel popularised on Windows Phone 7. You can use the Start screen as a program launcher, but it's actually a lot more. Perhaps best thought of as an amalgam of the traditional Windows task bar and start menu, along with the Windows Phone 7 start screen, it gives you a panoramic scrolling view of a series of application tiles. These can be familiar application icons for traditional desktop applications, or Windows Phone-style Live Tiles, displaying application information for an at-a-glance view of what's important to you.

Listening to Microsoft staff talk about Windows 8, two words keep coming up: 'fluid' and 'immersive'. The easy-scroll Start view is certainly fluid, with a very smooth action. Scrolling to the end of program list is quick and easy, with smooth panning. Tiles can be small or large, with different layouts for different screen sizes. The default widescreen view is groups three tiles high, while larger screens allow you to group four or five tiles high. Groups of tiles can be used to organise information and applications, without using folders.

If you've got a lot of items on the Start screen, you can use what Microsoft is calling 'semantic zoom' to quickly zoom out from the panoramic view, giving you a less detailed view of more tiles — much like looking down from 10,000 feet! Although you lose much of the detail and information on Live Tiles, you can still see what they are, hence the name. Once you're in semantic zoom view, you can quickly move to the tile you want to use, or reorganise tiles and groups.

Touch keyboard
Slate devices get access to a touch keyboard, which uses tools developed for Windows Phone 7 to make it a lot easier to type on-screen. Fuzzy hot targeting uses predictive text to guess which key you'll use next, expanding the hit target around the most likely keys. Built-in autocomplete uses a dynamic insert key to quickly drop words into your text. There's no need to remove your fingers from the keyboard, and as it's all built into the Windows 8 controls, developers don't need to do anything to use the feature in their applications.

The Windows 8 keyboard also includes a split layout for thumb typing on tablets, and supports handwriting recognition on devices with pen digitisers. If you've used a tablet PC in the past, you'll find Windows 8's pen support very familiar.

You're not limited to using touch, as there's full support for mouse and keyboard, with a range of keyboard shortcuts for the power user. When you use a mouse, the 'charms' — Search, Share, Start, Devices and Settings icons — move to the lower left. Other alternatives to touch gestures include opening the app bar with a right mouse click, and clicking and dragging on the left edge of the screen to handle application snapping. There's also support for horizontal scrolling using the mouse scroll wheel, and the Windows key will always take you back to the start screen.

Applications
Metro is everywhere in Windows 8. You'll find it in the settings application, in the task manager, and of course in the new Metro-style applications. Previously referred to as 'immersive' applications, Metro applications are full-screen applications with no chrome — once launched, they take over the entire screen. There are no commands visible, just the content.

If you've got a touch device, you can use the same gestures as on the Start screen to interact with your touch applications — with additional gestures that help you navigate between applications and the Start tools. Slide up from the bottom of the screen and you'll open the app bar, which hosts the available commands and can appear at the top or bottom of the screen (or both, like Internet Explorer, which uses the top of the screen for tabs and the bottom for the address bar and tabs). Applications can expose key elements as secondary tiles, which are deep links to features and content inside an application. You can pin these to the start screen, where they behave just like any other tile.

Windows 8 applications can be part-pinned to the side of the screen, showing a separate mini-UI, while a second application has a slightly reduced full-screen experience

If you swipe in from the right you'll see a set of five icons — which Microsoft calls 'charms' — for Search, Share, Start, Devices and Settings, along with the clock and a set of system notifications. Charms are a quick way of accessing system and application functions — just tap a charm and a pane opens up showing you quickly what you need to do. Tap Settings, for example, and you can work with network settings, volume and brightness, as well as notifications and power management.

Swipe from the left and you can page through the currently running applications. You can also drag an application from the left onto the screen, and snap it in place. You can then use a slider to change the view, between a near full-screen view and a narrow view with a subset of the application's user interface. It's easy to change, and means you can be looking at IM messages in one view while working with email in another (or playing a game…). The snapped minimised view is live, so you can use it to host video while working in an immersive application. The swipe gesture is also how you take advantage of Windows multitasking: you can switch between several applications quickly, with the Windows 8 memory management tools handling the application lifecycle, closing Metro applications down or suspending them to disk.

Internet Explorer 10
IE 10 also gets the immersive look-and-feel. The result is a very different browser, focused purely on content. It's fast and easy to use, with the same swipe gestures as the rest of Windows 8, taking advantage of the OS's new rendering tools to deliver crisp, clear text. Opening the app bar also shows a tab view, with live snapshots of other windows, just a tap away. It's easy to open new tabs, and just as easy to make them private, holding down the new tab button to launch InPrivate sessions in the same application Window — a major change from earlier versions of IE.

One thing we found with the new IE was how little we had to type. Autocomplete in the address bar works with your history to quickly fill in site addresses, while new tabs open with a frequent sites view — just tap a site icon in the frequent sites view to open the page. IE 10 has more slots for frequent sites that IE 9, making it easier to jump straight to a page. You can also pin pages on the start screen, much like the current task bar pinning in IE 9, with the ability to deliver information from the web on a Live Tile.

There won't be a new Internet Explorer Platform Preview for Windows 7. Internet Explorer development is now taking place in Windows 8, and Microsoft doesn't want to confuse developers by providing a test environment on another version of Windows.

Sharing and Contracts
One of the most important concepts in Windows 8 is the 'contract'. This is how applications can work together, using Windows 8 infrastructure to share information and services, without needing any knowledge of other applications. Windows 8 handles the interactions, exposing functionality through the aforementioned 'charms'.

Applications that can share information are exposed using the Share charm, if they implement the Windows 8 Share contract. If you choose an application it loads in the charm space, with its own user interface, and takes in and processes the data shared from another application. It's a process analogous to the Windows clipboard, although it involves much more than just text and links.

The Search charm supports another of Windows 8's contracts, and you can use it to see all the applications that support search — online and locally. It's an approach that's very similar to the SuperApps in BlackBerry, providing tools for delivering contextual computing in Windows.

Windows 8's file manager is built using Metro, and lets you pan quickly through large libraries, with thumbnails rendering much quicker than in Windows 7. There's support for the familiar library model, as well as for links to external applications and services. The file manager implements the Windows 8 picking contract, letting you mix local and external content in one place, ready for sharing or using in another application.This approach lets you bring together several applications to complete tasks, using Windows 8 contracts to link applications.

Although the Windows 8 user experience may look like one application running at a time, it's really a web of connected applications running together, and displaying results and connections in a live Start screen.

Devices
External devices, like printers, plug into the Devices charm using device-specific contracts. Any application can use the printer contract, and Windows 8 comes with support for many common printers. Device manufacturers can add their own applications to the Devices charm — Microsoft demonstrated a tool for handling printer settings developed by HP.

The Windows Desktop
Not all applications can be — or even need to be — Metro-style applications, and the familiar Windows desktop is just a tap away. If you launch a non-Metro application, the desktop opens with the application running. You can use touch, but with applications like Photoshop or the Office tools a mouse remains the best way to interact accurately.

Once the desktop is open you can flick through it like other applications, and can even take advantage of Windows 8's snapping tools to view desktop applications while working with Metro code. When you're done with the desktop it closes, leaving you with Metro. Microsoft has made a brave decision in turning the desktop into an application that only runs when needed, but this was necessary to encourage the development of Metro-style applications.