Tips & Tricks

System Administration


Serial Connection to the SGI

The serial console can be used to install system software on an SGI computer that has not display attached. A terminal is hooked up to serial port #1 and the boot messages are displayed over there. Instead of a terminal it is also possible to use another computer running a terminal emulation software like minicom on UNIX or TeraTerm on Windows.

Setting up the terminal is pretty easy. The settings required on the terminal (or emulation software) are 9600 baud, 8 data bits, no parity and 1 stop bit (short: 9600 8N1). Disable both hardware and software flow control to get this running. Connect the computer and the terminal using a null-modem cable. Start the termial and when it is listening start the SGI. Here you go...

If you want to use another SGI with the terminal software it is recommended you attach the null-modem cable to serial port #2. To get this to work properly you have to stop the getty for the port used (that's why we use serial port #2 here, port #1 might be needed when you want to connect to this machine using the serial port). The getty can be disabled by disabling the line for serial port #2 in /etc/inittab. It should look something like that before:

t2:23:off:/sbin/suattr -C CAP_FOWNER,CAP_DEVICE_MGT,CAP_DAC_WRITE+ip -c "exec /s
bin/getty -N ttyd2 co_9600"             # port 2


Booting into Single User

This couldn't be easier. To boot the system into single user mode enter the command monitor from the maintenance menu (press ESC or click on the button when the system asks you after passing POST). Inside the command monitor you are presented a prompt on which you have to type single to boot the machine into the single user mode using the installed operating system.

This is very helpful if you have messed up your network configuration in a way that doesn't allow the system to come up properly. You are asked for the root password if the system has booted to singleuser mode.