Apple Exclaves

On Apple Exclaves Random Augustine · Follow 17 min read · Feb 28, 2025 -- Listen Share The Issue with Monolithic Operating System Kernels Modern operating systems typically divide their operations into two main protection domains: the unprivileged domain (user mode) and the privileged domain (kernel mode). Software spends most of its time running in user mode, where it is restricted from directly performing powerful operations such as accessing files or communicating on a network. To carry out these actions, software must temporarily elevate to kernel mode by making a system call, which is a request to the kernel to take over and perform the desired operation. For example, when a program wants to open a file, it makes a system call which switches the program to running kernel code in kernel mode. The kernel code verifies the program is allowed to access that file, and then returns a special handle representing the now opened file back to the program in user mode. Most operating syst ... Read full article.