The kernel is the privileged core of an operating system. It controls memory, schedules work on the processor and hosts the kernel-mode drivers that talk directly to hardware on behalf of everything else.
In practice
When a network adapter receives data, it signals the processor with an interrupt. Code inside the kernel, including the adapter's driver, responds immediately, places the data in memory and hands it upward. This happens far below any application, at a privilege level ordinary programs cannot reach.
Common confusion
Kernel is often used loosely to mean the whole operating system. Strictly it refers to the smallest trusted layer. Not every driver runs in the kernel either: many printer and some USB drivers run in user mode, where a fault affects only that component instead of the whole system.
Why it matters to readers
Because kernel code has full access to the machine, Windows insists that kernel drivers be properly signed on 64-bit editions. That requirement shapes how drivers are packaged and published, and it explains why unsigned kernel drivers are refused during normal operation.
A closer look
Most people never interact with the kernel directly, yet its health affects everything they do. When a kernel-mode driver encounters a fault it cannot recover from, Windows stops the whole system to protect data, producing the familiar stop screen. The stop code and the named driver file, when shown, describe where the fault happened rather than proving that file was the root cause.
