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On an embedded system where the kernel will be rewritten if the available hardware changes), configured by the user (typical on older PCs and on systems that are not designed for personal use) or detected by the operating system at run time (normally calledplug and play). A kernel must maintain a list of available devices. For example, to show the user something on the screen, an application would make a request to the kernel, which would forward the request to its display driver, which is then responsible for actually plotting the character/pixel. Implementing a language, sometimes high-level (Example PostScript). A microkernel runs most of the operating system’s background processes in user space, to make the operating system more modular and, therefore, easier to maintain.

For example, a monolithic kernel executes all the operating systeminstructions in the same address space in order to improve the performance clarification needed of the system.

Various kernel designs differ in how they manage system calls and resources. When a computer program (in this context called a process) makes requests of the kernel, the request is called a system call. This separation is made in order to prevent user data and kernel data from interfering with each other and thereby diminishing performance or causing the system to become unstable (and possibly crashing). The kernel performs its tasks, such as executing processes and handling interrupts, in kernel space, whereas everything a user normally does, such as writing text in a text editor or running programs in a GUI (graphical user interface), is done in user space.