boot —
system bootstrapping procedures
Normally, the system will reboot itself at power-up or after crashes. An
  automatic consistency check of the file systems will be performed, and unless
  this fails, the system will resume multi-user operations.
The X68000/X68030 system boots from the device which is determined by the
  configuration of battery-backuped SRAM. By default, the boot ROM attempts to
  boot from floppy disk drives (from 0 to 3) first, and then attempts to boot
  from hard disk (SASI or SCSI). On the NetBSD/x68k,
  booting from SCSI disks (sd??) and 2HD floppy disks (fd?a, fd?c) is currently
  supported.
When the floppy disk is selected as the boot device, the initial program loader
  of the IOCS (firmware) reads the fdboot_ufs program at
  the top of the disk, and then the fdboot_ufs program loads the
  /boot program from the FFS or LFS file system.
  Normally, the /boot program then loads the
  NetBSD kernel /netbsd from the
  same floppy. In addition, the /boot program has
  abilities to uncompress gzip'ed kernels, to read the kernel from other disks
  of other file systems etc (see below).
For floppy disks, fdboot_ustar is also
    provided to read large kernels which do not fit one a single floppy.
When a SCSI hard disk is selected as the boot device, the initial program loader
  on the SCSI host adapter's ROM reads the operating system-independent IPL menu
  program at the top of the disk. The IPL menu program recognizes the partition
  table, and selects the partition to read the operating system kernel. During
  this phase, when the HELP key on the keyboard is pressed, the IPL menu program
  displays the partition menu of that disk to prompt the user to select the boot
  partition (although the NetBSD implementation of the
  IPL menu, /usr/mdec/mboot, does not have this
  functionality).
Next, the IPL menu reads the OS-dependent boot program from the
    top of the selected partition. For NetBSD FFS/LFS
    file systems sdboot_ufs is used. The
    sdboot_ufs program then loads the
    /boot program from that partition.
Once running, a banner similar to the following will appear:
NetBSD Multi-boot, Revision 1.1
(user@buildhost, builddate)
Press return to boot now, any other key for boot menu
booting sd0a:netbsd - starting in 5
 
After a countdown, the system image listed will be loaded. (In the
    example above, it will be
    “sd0a:netbsd” which is the file
    netbsd on partition “a” of the
    NetBSD SCSI hard disk of ID 0. Pressing a key within
    the time limit will enter interactive mode.
In interactive mode, the boot loader will present a prompt, allowing input of
  these commands:
  - boot[device:][filename]
    [- -adqsv]
- The default device will be set to the disk that the
      boot loader was loaded from. To boot from an alternate disk, the full name
      of the device should be given at the prompt. device
      is of the form
      xd[N[x]]
      where xd is the device from which to boot,
      N is the unit number, and x is
      the partition letter.
    The following list of supported devices may vary from
        installation to installation: 
      - sd
- SCSI disks on a controller recognized by the IOCS. The unit number is
          the SCSI ID.
- fd
- Floppy drives as numbered by the IOCS.
 The default filename is
        netbsd; if the boot loader fails to successfully
        open that image, it then tries netbsd.gz
        (expected to be a kernel image compressed by
        gzip(1)). Alternate
        system images can be loaded by just specifying the name of the
      image. Options are: 
      - -a
- Prompt for the root file system device, the system crash dump device,
          and the path to
          init(8).
- -d
- Bring the system up in debug mode. Here it waits for a kernel debugger
          connect; see
        ddb(4).
- -q
- Boot the system in quiet mode.
- -s
- Bring the system up in single-user mode.
- -v
- Boot the system in verbose mode.
 
- help
- Print an overview about commands and arguments.
- ls[path]
- Print a directory listing of path, containing
      inode number, filename and file type. path can
      contain a device specification.
- halt
- Reboot the system.
 
Note for X68030+MC68030 systems: Nothing special to be attended to; you can boot
  NetBSD just like as other operating systems such as
  Human68k and OS-9.
Note for X68030/040turbo(68040 accelerator by BEEPs) systems:
    NetBSD can boot under 040 mode. It can also boot
    under 030 mode if you have MC68030 on the board.
Note for X68000/Xellent30(68030 accelerator by TSR)+MC68030
    systems: In order to boot NetBSD, you must choose
    030 mode by using CH30.SYS, which must reside in the
    battery-backuped SRAM.
Note for X68000/Jupiter-X(68040/060 accelerator by FTZ-net)
    systems: The system must be in 040/060 processor mode.
  - /netbsd
- system code
- /netbsd.gz
- gzip-compressed system code
- /usr/mdec/xxboot_ufs
- boot block (read by installboot), xx is disktype
- /usr/mdec/boot
- source of /boot (can be just copied to the root directory)
- /boot
- main part of the boot program