What does the Unix/linux kernel play in the system?

What role does the Unix/linux kernel play in the system?

Not just the FreeBSD system, every operating system has a kernel -- from MS-DOS, Windows to advanced terminal mainframes, but various systems have different attitudes toward the kernel, and some systems cost a lot. Great effort to hide the kernel from the user. Both the release version of Windows or UNIX systems have a default kernel, and each time a new version is released, most of the changes are provided for driver support for new devices. The kernel is responsible for echoing the devices connected to the system, which is why Windows needs to install drivers for new or previously unsupported devices, and generally needs to reboot the system - because the kernel has been modified, in order to use the new The kernel must be restarted, otherwise the system will be required to load the new device as a kernel extension or module. From the perspective of the kernel architecture, FreeBSD uses a microkernel architecture, which means that the kernel is small and modular. Windows NT and Mach (the kernel based on Mac OS X) are just a few examples of microkernels in which new devices are typically added to the system by pseudo-kernel modules—these modules may be loaded and loaded while the system is running. Uninstall without recompiling the kernel. But Linux and Windows 9x systems are monolithic kernels, where the kernel code is optimized from a performance perspective and is as easy to maintain as possible, but every time a new device is added to the system. The system administrator will be asked to recompile the kernel.

This is not a very accurate description - Linux is trying to modularize the kernel. The FreeBSD kernel has to be recompiled for these different reasons. The difference between the microkernel and the overall kernel is very large. There should be a theoretical problem, not just the difference in device support. The most basic difference between the two is that the microkernel provides a user processing level or ring that supports non-system calls, rather than all within the system. The core of Iwashiro is reduced to include only the best programs, which means that the kernel contains the highest level of the required execution state in the monitoring mode, in order to increase the robustness of the kernel operation and ensure kernel processing. The process is easy to understand and manage, and it is easy to modularize the device.

Although the above is quite good, unfortunately, it is unrealistic to meet the requirements of each device type and option that can be modularized and can be loaded at runtime. After some experience with FreeBSD, readers will realize this and will find that it is inevitable to recompile the kernel anyway.

Where is the Windows kernel?

The kernel in Windows is an executable file in C:\\Windows\\System:

Where is the UNIX kernel?

On many UNIX systems, the location of the kernel is usually located at the top of the file system; the kernel of the FreeBSD system is placed in /boot.