Give a short listing of the files in the root directory of the default
boot device, as a hint about available boot files.
may also be specified as the last segment of a path, in which case
the listing will be of the relevant subdirectory.)
.Sm off bios_drive: interface( unit,[slice,part]) filename
.Sm on [-aCcDdghmnPprsv] [-Sspeed]
|Specify boot file and flags.|
|The drive number as recognized by the BIOS. 0 for the first drive, 1 for the second drive, etc.|
The type of controller to boot from.
Note that the controller is required
to have BIOS support since the BIOS services are used to load the
boot file image.
The supported interfaces are:
|ad||ST506, IDE, ESDI, RLL disks on a WD100 or lookalike controller|
|fd||5 1/4" or 3 1/2" High density floppies|
|da||SCSI disk on any supported SCSI controller|
|unit||The unit number of the drive on the interface being used. 0 for the first drive, 1 for the second drive, etc.|
The partition letter inside the
portion of the disk.
By convention, only partition
contains a bootable image.
If sliced disks are used
(1 for the first slice, 2 for the second slice, etc.)
can be booted from, with the default (if not specified) being the active slice
or, otherwise, the first
.Fx slice. If slice is specified as 0, the first
.Fx slice (also known as "compatibility" slice) is booted from.
|The pathname of the file to boot (relative to the root directory on the specified partition). Defaults to /boot/kernel/kernel. Symbolic links are not supported (hard links are).|
|-a||during kernel initialization, ask for the device to mount as the root file system.|
|-C||try to mount root file system from a CD-ROM.|
|-c||this flag is currently a no-op.|
|-D||boot with the dual console configuration. In the single configuration, the console will be either the internal display or the serial port, depending on the state of the -h option below. In the dual console configuration, both the internal display and the serial port will become the console at the same time, regardless of the state of the -h option.|
|-d||enter the DDB kernel debugger (see ddb(4)) as early as possible in kernel initialization.|
|-g||use the GDB remote debugging protocol.|
|-h||force the serial console. For instance, if you boot from the internal console, you can use the -h option to force the kernel to use the serial port as its console device. The serial port driver sio(4) (but not uart(4)) has a flag (0x20) to override this option. If that flag is set, the serial port will always be used as the console, regardless of the -h option described here.|
|-m||mute the console to suppress all console input and output during the boot.|
|-n||ignore key press to interrupt boot before loader(8) is invoked.|
|-P||probe the keyboard. If no keyboard is found, the -D and -h options are automatically set.|
|-p||pause after each attached device during the device probing phase.|
|-q||be quiet, do not write anything to the console unless automatic boot fails or is disabled. This option only affects second-stage bootstrap, to prevent next stages from writing to the console use in combination with the -m option.|
|-r||use the statically configured default for the device containing the root file system (see config(8)). Normally, the root file system is on the device that the kernel was loaded from.|
|-s||boot into single-user mode; if the console is marked as "insecure" (see ttys(5)), the root password must be entered.|
|set the speed of the serial console to speed. The default is 9600 unless it has been overridden by setting BOOT_COMCONSOLE_SPEED in make.conf(5) and recompiling and reinstalling the boot blocks.|
|-v||be verbose during device probing (and later).|
Use the /boot.config file to set the default configuration options for the boot block code. See boot.config(5) for more information about the /boot.config file.
/boot.config parameters for the boot blocks (optional) /boot/boot1 first stage bootstrap file /boot/boot2 second stage bootstrap file /boot/loader third stage bootstrap /boot/kernel/kernel default kernel /boot/kernel.old/kernel typical non-default kernel (optional)
When disk-related errors occur, these are reported by the second-stage bootstrap using the same error codes returned by the BIOS, for example "Disk error 0x1 (lba=0x12345678)". Here is a partial list of these error codes:
0x1 Invalid argument 0x2 Address mark not found 0x4 Sector not found 0x8 DMA overrun 0x9 DMA attempt across 64K boundary 0xc Invalid media 0x10 Uncorrectable CRC/ECC error 0x20 Controller failure 0x40 Seek failed 0x80 Timeout
NOTE: On older machines, or otherwise where EDD support (disk packet interface support) is not available, all boot-related files and structures (including the kernel) that need to be accessed during the boot phase must reside on the disk at or below cylinder 1023 (as the BIOS understands the geometry). When a "Disk error 0x1" is reported by the second-stage bootstrap, it generally means that this requirement has not been adhered to.
ddb(4), boot.config(5), make.conf(5), ttys(5), boot0cfg(8), btxld(8), config(8), gpart(8), gptboot(8), halt(8), loader(8), nextboot(8), reboot(8), shutdown(8)
The bsdlabel format used by this version of BSD is quite different from that of other architectures.
Due to space constraints, the keyboard probe initiated by the -P option is simply a test that the BIOS has detected an "extended" keyboard. If an "XT/AT" keyboard (with no F11 and F12 keys, etc.) is attached, the probe will fail.