Handy tip: What causes Blue Screen of Death in Windows 10?

windows blue screen death crash freeze
Thinkstock

To solve Windows 10 system crashes, you need to understand what causes the dreaded Blue Screen of Death in Windows 10.

Windows 10 operates in both Kernel Mode and User Mode. The idea is simple; run core operating system code and device drivers in Kernel Mode and software applications and user mode drivers in User Mode. For applications to access the services of the OS and the hardware, they must call upon Windows services that act as proxies. Thus, by blocking User Mode code from having direct access to Kernel Mode, OS operations are generally well protected.

The problem is when Kernel Mode code goes awry. In most cases, it is third-party drivers living in Kernel Mode that make erroneous calls, such as to non-existent memory or to overwrite OS code, that can result in system failures. And, yes, it is true that Window itself is seldom at fault.

Kernel Mode software has complete and unfettered access to the hardware. Software operating here is normally the most trusted because it can execute any instruction and reference any address in the system. Crashes in Kernel Mode are complete system failures requiring a reboot. This is where you find the operating system kernel code and most drivers.

+ MORE WINDOWS 10: Keep up to date with the latest on Windows 10 +

User Mode software cannot directly access the hardware or reference any address freely. It must pass instructions - perhaps more accurately requests - through calls to APIs. This feature enables protection for the overall operation of the system, regardless of whether an application makes an erroneous call or tries to access an inappropriate address. Crashes in User Mode are generally recoverable, requiring a restart of the application but not the entire system. This is where you find most of the code running on your computer ranging from Microsoft Word to a browser and some drivers.

So, with much of the software running in User Mode these days, there is simply less opportunity for applications to corrupt system-level software and, for that matter, each other. However, kernel-mode software is not protected from other kernel-mode software. For example, if a video driver erroneously accesses a portion of memory assigned to another program (or memory not marked as accessible to drivers) Windows will stop the entire system.

This story, "Handy tip: What causes Blue Screen of Death in Windows 10?" was originally published by Network World.

Computerworld's IT Salary Survey 2017 results
Shop Tech Products at Amazon