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

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

Not only FreeBSD systems, each operating system has a kernel---from MS-DOS, Windows to advanced terminal mainframes, but various systems have different attitudes towards the kernel, and some systems have spent a lot of time hiding the kernel from the user. Both the Windows or UNIX system distributions have a default kernel, and most of the changes made to the new device provide driver support each time a new version is released. The kernel is responsible for echoing devices connected to the system, which is why Windows needs to install drivers for new or previously unsupported devices, and generally requires a reboot-because the kernel has been modified and the system must reboot to use the new kernel. Otherwise, the system will require that the new device be extended or loaded as a kernel.

From the core architecture, FreeBSD uses the microkernel (microkernel) architecture, which means the kernel is small and modular. Windows NT and Mach (Mac OS x based kernels) are a few other examples of microkernel, where new devices are typically added to the system by pseudo kernel modules---these modules may be loaded and unloaded while the system is running without recompiling the kernel. But the Linux and Windows 9x systems are the overall kernel (monolithic kernel), where kernel code is optimized as much as possible and makes it easy for developers to maintain, but each time a new device is added to the system, The system administrator is required to recompile the kernel.

This is not a very accurate description---Linux is trying to modularize the kernel, FreeBSD kernel for these different reasons must be recompiled, the difference between the micro-kernel and the overall core should be 骒 a theoretical problem, not only in the device support is different, The basic difference between the two is that the microkernel provides a user-processing level or loop that supports non-system calls, not all within the system, allowing the core of the rock generation Lang to be streamlined to include only the essence of the program, which means that the kernel contains all the highest levels that must be required to perform the state in the guardianship mode, is to increase the robustness of the kernel operation, and ensure that the kernel process is easy to understand and manage, but also easy to achieve the modularization of the device.

Although all of these are good, unfortunately, each device type and option can be modular and can be run at runtime, the 崊 of loading requirements is just as unrealistic as the Lord, and after having a certain FreeBSD use experience, readers Kuai realize that it is inevitable that the kernel will need to be recompiled anyway.

Where is the Windows kernel?

In Windows, the kernel is an executable file in C:windowssystem:

　Where is the Unix kernel?

In many UNIX systems, the location of the kernel is usually located at the root of the file system, while the kernel of the FreeBSD system is placed in the/boot.