Chapter 5. Booting the Installation System If this is the first time you’re booting the system, try the default boot parameters (i.e., don’t try setting parameters) and see if it works correctly. It probably will. If not, you can reboot later and look for any special parameters that inform the system about your hardware. Information on many boot parameters can be found in the Linux BootPrompt HOWTO (http://www.tldp.org/HOWTO/BootPrompt-HOWTO.html), including tips for obscure hardware. This section contains only a sketch of the most salient parameters. Some common gotchas are included below in Section 5.4. If you are booting with a serial console, generally the kernel will autodetect this. If you have a video- card (framebuffer) and a keyboard also attached to the computer which you wish to boot via serial console, you may have to pass the console= device argument to the kernel, where device is your serial device, which is usually something like ttyS0 . You may need to specify parameters for the serial port, such as speed and parity, for instance console=ttyS0,9600n8 ; other typical speeds may be 57600 or 115200. Be sure to specify this option after “---”, so that it is copied into the bootloader configuration for the installed system (if supported by the installer for the bootloader). In order to ensure the terminal type used by the installer matches your terminal emulator, the pa- rameter TERM= type can be added. Note that the installer only supports the following terminal types: linux , bterm , ansi , vt102 and dumb . The default for serial console in debian-installer is vt102 . If you are using a virtualization tool which does not provide conversion into such terminals types itself, e.g. QEMU/KVM, you can start it inside a screen session. That will indeed perform translation into the screen terminal type, which is very close to vt102 . The installation system recognizes a few additional boot parameters 1 which may be useful. A number of parameters have a “short form” (or alias) that helps avoid the limitations of the kernel command line options and makes entering the parameters easier. If a parameter has a short form, it will be listed in brackets behind the (normal) long form. Examples in this manual will normally use the short form too. This parameter sets the lowest priority of messages to be displayed. The default installation uses priority=high . This means that both high and critical priority messages are shown, but medium and low priority messages are skipped. If problems are en- countered, the installer adjusts the priority as needed. If you add priority=medium as boot parameter, you will be shown the installation menu and gain more control over the installation. When priority=low is used, all messages are shown (this is equivalent to the expert boot method). With priority=critical , the installation sys- tem will display only critical messages and try to do the right thing without fuss. Note: In order to get asked for a VLAN configuration during the network setup a priority of medium or low is needed. 1. With current kernels (2.6.9 or newer) you can use 32 command line options and 32 environment options. If these numbers are exceeded, the kernel will panic. 35 debconf/priority (priority) 5.3.2. Ubuntu Installer Parameters 5.3.1. Boot console