macOS<\/a> is a series of proprietary graphical user interface<\/a> operating systems developed and marketed by Apple Inc.<\/a> since 2001. It is the primary operating system for Apple's Macintosh<\/a> computers. Within the market of desktop and laptop computers, it is the second most widely used desktop OS, after Microsoft Windows<\/a> and ahead of ChromeOS<\/a>.<\/p> The system is built on a Unix<\/a> foundation and is based on the Darwin OS<\/a> open-source project. Its core architecture utilizes the XNU Kernel<\/a>, which combines the Mach Microkernel<\/a> and FreeBSD<\/a> components. Historically, macOS<\/a> was derived from NeXTSTEP<\/a>, the operating system developed at Steve Jobs<\/a>'s company NeXT<\/a> before Apple acquired it in 1997.<\/p> Modern iterations of the software, such as macOS Sonoma<\/a>, are heavily optimized for Apple Silicon<\/a>, including the M1 Chip<\/a>, M2 Chip<\/a>, and M3 Chip<\/a>. This transition from Intel<\/a> processors has enabled features like the Neural Engine<\/a> for machine learning tasks and native support for iOS<\/a> and iPadOS<\/a> applications. Key system features include the Finder<\/a>, Spotlight<\/a>, Mission-Control<\/a>, and Time Machine<\/a> for backups.<\/p> Detailed technical documentation and release notes can be found at the Apple Developer Portal<\/a> and comprehensive history is available via Wikipedia<\/a>.<\/p>