Mach blocked意思

"Mach blocked" is a term used in the context of operating systems, particularly in the Mach microkernel, which is a core part of several Unix-like operating systems, including macOS and iOS. When an operation is "Mach blocked," it means that the process is waiting for a Mach message to be processed or delivered.

In the context of macOS and iOS, the Mach microkernel is responsible for managing low-level operations such as inter-process communication, memory management, and task management. When a process needs to communicate with another process or wait for an event to occur, it may enter a state of "Mach blocking," where it suspends its execution and waits for the message or event to become available.

For example, when a process issues a system call that requires interaction with the kernel, the process may be put into a Mach-blocked state until the kernel completes the requested operation and sends a response message back to the process.

Mach blocking is a fundamental aspect of how processes interact with the kernel and with each other in a Mach-based operating system. It is a form of cooperative multitasking where processes voluntarily give up CPU time by blocking themselves when they are waiting for I/O or other events. This allows the kernel to schedule other ready processes and improve overall system responsiveness and efficiency.