What is "ntoskrnl.exe"

ntoskrnl.exe (Short for Windows NT operating system kernel,) also known as kernel image, provides the kernel and executive layers of the Windows NT kernel space, and is responsible for various system services such as hardware virtualization, process and memory management, thus making it a fundamental part of the system. It contains the cache manager, the executive, the kernel, the security reference monitor, the memory manager, and the scheduler.