Why does this happen?

Windows became more stable as it matured. And, while the operating system has gone from 16-bit to 32-bit and now 64-bit, the features have become more extravagant, and the footprint much larger – it is actually harder to bring down. Still, it does fall over. However, the reasons for such system failures have not changed from the XP days. Windows takes advantage of a protection mechanism that lets multiple applications run at the same time without stepping all over each other. Windows takes advantage of a protection mechanism that lets multiple applications run at the same time without stepping all over each other. Known now as User Mode and Kernel Mode, it was originally known as the Ring Protection scheme.

o Kernel Mode

Kernel Mode (Ring 0) 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.

o User Mode

User Mode (Ring 3) 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 accesses 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 Word to Solitaire 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 is known as a Bug Check and the familiar Blue Screen of Death is displayed.

Tips for fixing it:

o Getting Started: System Requirements

To prepare to solve Windows 7 system crashes using WinDbg you will need a PC with the following:

–  32-bit or 64-bit Windows 7/Vista/XP or Windows Server 2008/2003

–  Approximately 25MB of hard disk space (this does not include storage for dump files or for symbol files)

–  Live Internet connection

–  Microsoft Internet Explorer 5.0 or later

–  The latest version of WinDbg comes as an option in the Windows SDK. The SDK download file is called winsdk_web.exe, is 498KB in size, and can be downloaded for free. (Note that after installing the debugger you can delete the large download file thus freeing up lots of space.)

–  A memory dump (the page file must be on C: for Windows to save the memory dump file)

This entry was posted on Sunday, March 23rd, 2014 at 10:00 am and is filed under Windows FTP. You can follow any responses to this entry through the RSS 2.0 feed. Responses are currently closed, but you can trackback from your own site.