halt - halt system
halt shuts the system down. A clean shutdown is performed, flushing buffers to disk, unmounting filesystems, and so forth.
Once shutdown is complete, halt stops execution of the operating system. What this entails depends on the platform. On platforms with a hardware boot monitor, it normally returns to the boot monitor. On software-based platforms, such as System/161, it normally terminates the software simulation. On other platforms the system will generally wait for a keystroke on the console and then reboot.
halt uses the reboot system call.
halt will function properly even before you do any work on OS/161.