Extreme TLDR: Deep dive on Apple’s Darwin OS and XNU kernel evolution from Mach/BSD roots to modern platforms. Explores hybrid design, adaptability, security features, and historical milestones from NeXTSTEP acquisition to Apple Silicon. XNU combines microkernel attributes (Mach) with monolithic performance (BSD), facilitating kernel flexibility and efficiency across macOS and iOS devices. Key developments include 64-bit and ARM support, virtualization strategies, and enhanced security across iterations.
https://tansanrao.com/blog/2025/04/xnu-kernel-and-darwin-evolution-and-architecture/