Microsoft stabilized Windows with a roaming ‘USB cart of death’.

Si alguna vez se ha preguntado cómo se las arregla Microsoft para que Windows siga funcionando sin problemas en millones de configuraciones de hardware diferentes, es posible que le interese conocer el «Carrito USB de la Muerte». Este es un dispositivo que los ingenieros de Microsoft utilizan para probar la compatibilidad y estabilidad de Windows con varios dispositivos y controladores USB.

The USB Cart of Death is essentially a cart full of USB hubs, cables and devices that can be connected to a Windows PC. The device can simulate various scenarios, such as connecting and disconnecting devices, changing ports, changing power states and causing errors. The goal is to expose any bugs or vulnerabilities in the Windows kernel, driver stack or device firmware that could cause crashes, freezes or data loss.

The USB Cart of Death was first introduced in 2011, when Microsoft was developing Windows 8. At the time, Windows had a reputation for being unstable and prone to displaying blue screens of death (BSOD), especially when it came to USB devices. Microsoft wanted to improve the reliability and performance of Windows, and one of the ways to do that was to rigorously test it with the USB Cart of Death.

According to a blog post by Microsoft engineer Raymond Chen, the USB Cart of Death was so effective at finding bugs that it became a legend among the Windows team. Chen wrote:

«The USB Cart of Death was so good at finding bugs that it became a sort of walking grim reaper. If you saw the USB Cart of Death parked outside your office, you knew your day was about to get a lot worse.»

The USB Cart of Death helped Microsoft fix hundreds of bugs and improve the quality of Windows 8 and later versions. Chen claimed that the device reduced the number of BSODs caused by USB problems by 90%. He also said the device was not only useful for testing Windows, but also for testing USB devices themselves. He wrote:

«Sometimes we would find errors in the devices themselves. For example, we found a device that would fail if you plugged it into a USB 3 port instead of a USB 2 port. We reported this bug to the device vendor, who replied, ‘Oh, yes, we know about that bug.’ But nobody uses USB 3 yet, so we didn’t bother to fix it.»

The USB Cart of Death is still in use today as Microsoft continues to develop and update Windows 10 and Windows 11. The device is constantly being updated with new USB devices and drivers, as well as new scenarios and tests. The device is also used to verify Windows compatibility and security with various types of USB devices, such as keyboards, mice, cameras, printers, scanners, storage devices, audio devices and more.

The USB Cart of Death is an example of how Microsoft uses innovative and rigorous testing methods to ensure the quality and stability of Windows. The device also shows how Microsoft values feedback and bug reports from its customers and partners, as well as its own engineers. The appliance is a testament to Microsoft’s commitment to making Windows the best operating system for everyone.

In a recent video with Dave’s Garage, Raymond Chen, a veteran Windows developer, shared how Microsoft experimented with Windows 98 to test its compatibility with various USB devices. USB was a new technology at the time, so Windows 98 developers had to learn their way around it.

They came up with the «USB Death Cart». It was not lethal to humans, but it was lethal to countless versions of Windows. Whenever the USB Cart of Death was plugged into a Windows computer, a blue screen would often appear, indicating that the version of Windows on the PC was defective and needed to be repaired.

The USB Cart of Death had 64 USB devices, the maximum number of USB devices that Windows could support at the time (the limit is now 127). The Windows developers loaded the cart (which was actually a mail cart used for internal mail delivery) with all sorts of USB devices: keyboards, mice, printers, and even a USB gaming wheel, which they used to maneuver the cart. All of these devices were connected to the Windows PC under test via a single USB cable. To achieve this, they used several USB hubs.