$FreeBSD: src/sys/boot/README,v 1.3 2000/05/01 20:26:17 peter Exp $ $DragonFly: src/sys/boot/README,v 1.3 2003/11/10 06:08:19 dillon Exp $ README file, for the boot config file setup. This is meant to explain how to manage the loader configuration process. The boot and loading process is either defined, or being defined in boot(8) and loader(8). The ongoing development of the FreeBSD bootloader, and its rapid deployment while still in the development phase, has resulted in a large number of installations with outdated configurations. Those installations actively tracking the FreeBSD development should also ensure that their bootloader configurations are updated. If you see files discussed here that your system doesn't yet have, add them yourself. This is an effort to give the currently correct method for setting up your boot process. It includes information on setting up screen savers and plug and play information, and also on recording any changes you make in your kernel configuration. This file is temporary, because as I noted, the process is still undergoing development, and will still change. Man pages are coming out, but they're still going to be somewhat fragile for a while. If you note anything in here that's broken, it would be a good idea to report it to the FreeBSD-current list, or to Daniel C. Sobral or Mike Smith . NOTE: Please understand, all this is very current development, and while getting this working for STABLE is a goal, it's not yet ready for that. It's possible that parts of this might indeed work for stable, but if you're not absolutely sure what you're doing, you're better off not using the information in this README for STABLE. Use this for current only for a while longer, please! After the first two stages in the booting process (described in boot(8)), the last stage of the booting process, called the loader (see loader(8)) reads in the /boot/loader.rc file. The two lines you should have there are: include /boot/loader.4th start This reads the ficl (forth) initialization files, then /boot/default/loader.conf. This file, which strongly resembles in form /etc/rc.conf but functions quite differently, has spots for endless user customization but isn't yet completely finished. For one thing, it used to assume a /kernel.config instead of a /boot/kernel.conf. Watch the first few lines of /boot/defaults/loader.conf to see if the file name changes. [See the section at the end on loader.conf syntax] You don't actually want to make any changes to /boot/defaults/loader.conf, the file that is a hacking- target is: /boot/loader.conf and might very likely not exist yet on your system). You should copy /boot/defaults/loader.conf to /boot/loader.conf, and then cut out anything you didn't want changed. The start command also loads your kernel for you, so don't put any lines in there like "load kernel", they'll fail (but really have already worked for you). Start also reads in the file /boot/defaults/loader.conf and /boot/loader.conf. If you don't have /boot/loader.conf, you'll see a message on boot about it, but it's a warning only, no other effects. See the section on loader.conf syntax at the end of this document, for some more pointers on loader.conf syntax. The best way to manage splash screens is with entries in /boot/loader.conf, and this is very clearly illustrated in /boot/defaults/loader.conf (which you could just copy over to /boot/loader.conf). I'm going to illustrate here how you *could* do it in /boot/loader.rc (for information only) but I don't recommend you do this; use the /boot/defaults/loader.conf syntax, it's easier to get it correct. You can load your splash screen by putting the following lines into /boot/loader.rc: load splash_bmp load -t splash_image_data /path/to/file.bmp The top line causes the splash_bmp module to get loaded. The second line has the parameter "-t" which tells the loader that the class of DATA being loaded is not a module, but instead a splash_image_data located in file /path/to/file.bmp. To get your plug and play data correctly set, run kget, redirecting the output to /boot/kernel.conf. Note that kget right now adds an extra "q" to it's output (from the q for quit you press when you exit config), and if you want, you can remove that from the file. Kget reports data only, so feel free to run it, just to see the output. Make certain you have the kernel option USERCONFIG set in your kernel, so that you can do a boot -c, to initially set your cards up. Then, edit /boot/loader.conf so that the following line shows up (overwriting, in effect, a similar line in /boot/default/loader.conf): userconfig_script_load="YES" My own pnp line looks like: pnp 1 0 os irq0 15 irq1 0 drq0 1 drq1 0 port0 1332 (kget changes numbers from hexadecimal to decimal). Note that, at this moment, the change from using /kernel.config to using /boot/kernel.conf as the storage place for kernel config changes is going on. Take a look at your /boot/defaults/loader.conf, see what's defined as userconfig_script_name, and if you override, make sure the file exists. Note that the loader only has access to the root filesystem, so be careful where you tell it to read from. o If you interrupt autoboot, you'll engage interactive mode with loader. Everything you type will have the same effects as if it were lines in /boot/loader.rc. o While in interactive mode, you can get help by typing "?", "help [ []]" and "help index". These are mostly commands one would expect a normal user to use. I recommend you play with them a little, to gain further familiarity with what's going on. Note that it is not possible to damage or corrupt your system while experimenting with the loader, as it cannot write to any of your filesystems. o The command "unload" will unload everything. This is very useful. Once loader.rc has finished and the system is in the autoboot count-down, you will usually have the kernel and other modules loaded. Now, suppose your new /kernel is broken, how do you load /kernel.old? By typing: unload load kernel.old [any other modules you wish to load] boot o If you use loader.conf, you can do: unload set kernel=kernel.old boot-conf this will then load all the modules you have configured, using kernel.old as kernel, and boot. o From loader, you can use the command "more" to read the contents of /boot/loader.rc, if you wish. This is not FreeBSD's more. It is one of loader's builtin commands. Useful if you can't quite recall what you have there. :-) Of course, you can use this command to read anything else you want. o "boot -flag" works, "boot kernelname" works, "boot -flag kernelname" doesn't. "boot kernelname -flag" might work, but I'm not sure. The problem is that these flags are kernel's flags, not boot's flags. o There are a number of variables that can be set. You can see them in loader.conf, but you can get much more detailed information using the "help" command, eg. help set . o The variable root_disk_unit is particularly important, as it solves a relatively common problem. This problem shows when the BIOS assign disk units in a different way than the kernel. For example, if you have two IDE disks, one on the primary, the other on the secondary controller, and both as master, the default in most kernels is having the first as wd0, and the second as wd2. If your root partition is in wd2, you'll get an error, because the BIOS sees these disks as 0 and 1 (well, 1 and 2), and that's what loader tells the kernel. In this case, "set root_disk_unit=2" solves the problem. You use this whenever the kernel fails to mount to root partition because it has a wrong unit number. FILE OVERVIEW o /boot/defaults/loader.conf -- Master configuration file, not to be edited. Overridden by /boot/loader.conf. o /boot/loader.conf -- local system customization file, in form very much like /boot/defaults/loader.conf. This file is meant to be used by local users and the sysinstall process. o /boot/loader.conf.local -- local installation override file. This is intended for use by installations with large numbers of systems, to allow global policy overrides. No FreeBSD tools should ever write this file. o /kernel.config -- old location of kernel configuration changes (like pnp changes). o /boot/kernel.conf -- new location for kernel configuration changes. o /boot/loader.rc -- loader initial configuration file, chiefly used to source in a forth file, and start the configuration process. NOTES ON LOADER.CONF SYNTAX I'm copy here from the last 11 lines from /boot/defaults/loader.conf: ############################################################## ### Module loading syntax example ########################## ############################################################## #module_load="YES" # loads module "module" #module_name="realname" # uses "realname" instead of "module" #module_type="type" # passes "-t type" to load #module_flags="flags" # passes "flags" to the module #module_before="cmd" # executes "cmd" before loading module #module_after="cmd" # executes "cmd" after loading module #module_error="cmd" # executes "cmd" if load fails The way this works, the command processor used by the loader (which is a subset of forth) inspects these variables for their suffix, and the 7 lines above illustrate all the currently defined suffixes, and their use. Take the part before the underscore, and customize it i(make it unique) for your particular use, keeping the suffix to allow the particular function you want to activate. Extra underscores are fine, because it's only the sufixes that are scanned for. (authors Chuck Robey and Daniel Sobral).