A Megakernel (or megalithic kernel) is a kernel in which all the usual user mode software is in the kernel. This can range from the UI being in the kernel to the entire OS, along with utilities, UI and applications, being written into the kernel. This kernel architecture is very simple and efficient as it has no need for memory management or loading software, however it can run into issues that other kernels would not. An example of the Megakernel is Dreckig OS.