February 2001



This extremely rare prototype device is the Microsoft Avenger and it is believed as few as 25 were manufactured. It was the device that was used to pioneer the Microsoft Smartphone 2002 operating system (codename Stinger). The device was given the name “Avenger” as the team working on it thought it was a sexy design, but the codename “Emma Peel” did not have the same cachet. The curve on the back of the device was modelled on the wife of Frank Bradshaw, a contractor working on the project, who was laying on her stomach reading while he sketched out the designs for the plastics. Microsoft Stinger SideThe cerulean blue finish was achieved by using automotive paint that the Microsoft hardware team managed to procure at the time. The hole in the back of the device was designed to work with the belt-clip that shipped with a Motorola GSM handset at the time. The Stinger featured a 176 x 220 pixels monochrome screen, but the long-term aim was that Microsoft’s Smartphone OS would be offered on devices with a colour display. The goal of the product was to be small enough to be used with one hand, in direct contrast to earlier PDA devices with combined phone capabilities that required two-handed use. With the benefit of hindsight, some have questioned why the Stinger team decided to pursue a device with a keypad and soft key driven user experience (UX). People tend to forget that the first smartphone with a capacitive touch display did not start shipping till 2007 when the LG Prada was released (just ahead of the first Apple iPhone). At the time that Microsoft was developing Stinger and the Avenger prototype phone, resistive touch screens were really the only option. These typically used a stylus and the backlight needed to be set at a level that ruined battery life. The Texas Instruments OMAP chip used in the Avenger phone had numerous cutting-edge innovations. A major shift for the Avenger phone was the move from NOR to NAND flash memory – as less expensive option. Microsoft was able to pioneer a clever way of using NAND memory to speed up access to Flash memory and also the use of multiple cores in the processor. The way the radio stack was integrated into the chip was also a break-through design. Texas Instruments managed to integrate the radio stack into the OMAP chip. This had never been done before. Previous smartphones were significantly less integrated between the radio stack and operating system. However, Microsoft was worried about the security implications of a potential operating system hack that could potentially affect the radio stack. There were many challenges to overcome this issue given the wide-reaching security and performance concerns that had to be addressed. Microsoft worked extremely closely with Texas Instruments on some significant architectural work to address this and introduced the concept of “secure boot”. This has gone on to be a standard feature in almost every consumer product that is offered today. Another key milestone was that Stinger was the first device where Microsoft’s WinCE platform (which underpinned both Pocket PC and Stinger) was run on Arm rather than Intel chips. This meant that the whole foundation of the operating system had to be rebuilt to support Arm. The Avenger hardware was also critical milestone to test the Stinger OS as prior to its creation the only way Microsoft could implement and test its software was to run the Stinger OS on custom built PCs (called a CE PC) that had a special motherboard with a cellular radio for running the OS. The user interface was a standard desktop monitor and the team had to use a keyboard and mouse to try the software. Although this solution was viable for development work, it was hopeless from a usability standpoint. The Avenger hardware became the first phone prototype that made it possible to experience the user interface in the palm of a hand. Another breakthrough on the device was the ability to offer ‘full’ Internet access. This was delivered via Microsoft's Mobile Explorer “microbrowser” that could support both HTML (delivering “full” web content) and WML (the wireless mark-up language) which offered a subset of Internet content and was popular on phones at the time. Microsoft’s focus on usability extended to areas such as caller ID and smart calendaring. A good example of the smart calendar feature was that the phone would vibrate instead of ring when a user was in a meeting. A rare video shared by Neil Enns (who worked on the development team) can be found below. In the video, the phone takes almost one minute to boot up and you are then able to see a phone call being made and the web browser being used. One interesting footnote on the video is that the screen on the device is bigger than the user interface. This was because the development team wanted to be able to toggle between screen sizes to experiment with different screen resolutions. The screen on the prototype device was actually from a Pocket PC unit.