The advanced design of kernel has made Shaun OS much more stable, attractive. How does it work? I will give a full statement of what i think in my mind, the rule i take when i am coding. First of all, the support of kernel mode thread gives me a great convenience. When hardware’s initialization is done, five kernel mode threads will be created, which i call it ish(interrupt service helper) in code style. These threads are in sleep state by default, but they are waked up by some kernel interrupts, such as keyboard, mouse, network card, and so on. Each kernel thread occupies two pages(8k) memory, including kernel mode stack. I will describe each of it in detail.