Loading diagnostics without the diag operation
In addition to the procedure using the diag operation, diskless and dataless clients have another way of loading diagnostics from the network. You can boot a diskless or dataless client from the network the same way you do for normal use, but with the machine's key mode switch in the Service position.
If the client's key mode switch is in the Service position at the end of the boot process, hardware diagnostics from the server's SPOT are loaded. If a standalone client boots with the key mode switch in the Service position, the diagnostics (if installed) are loaded from the hard disk.