Under Mach, the IPC system was used for this role instead. To call system functionality, a program would ask the kernel for access to a port, then use the IPC system to send messages to that port. Although sending a message requires a system call, just as a request for system functionality on other systems requires a system call, under Mach sending the message is pretty much all the kernel does; handling the actual request would be up to some other program.
Under Mach the IPC system was used for this role instead To call system functionality a program would ask the kernel for access to a port then use the IPC system to send messages to that port Although sending a message requires a system call just as a request for system functionality on other systems requires a system call under Mach sending the message is pretty much all the kernel does; handling the actual request would be up to some other program