April 8, 2003 BOOT 8 sun3

### NAME

boot - system bootstrapping procedures

### DESCRIPTION

#### Power fail and crash recovery

Normally, the system will reboot itself at power-up or after crashes. An automatic consistency check of the file systems will be performed as described in fsck(8), and unless this fails, the system will resume multi-user operations.

#### Cold starts

A disk-boot program ``(`/usr/mdec/ufsboot`) will attempt to load ```netbsd` from partition A of the boot device, which must currently be an ``sd'' disk. Alternatively, network boot program ``(`/usr/mdec/netboot`) will load ```netbsd` from the NFS root as determined by the procedure described in diskless(8).

#### Boot program options

-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.

Any extra flags or arguments, or the <boot string> after the -- separator are passed to the boot PROM. Other flags are currently ignored.

At any time you can break back to the ROM by pressing the `L1' and `a' keys at the same time (if the console is a serial port the same is achieved by sending a `break'). If you do this accidentally you can continue whatever was in progress by typing `c' followed by the return key.

### FILES

```/netbsd`
  system code
```/usr/mdec/bootxx`
  first-level boot block for disks
```/usr/mdec/netboot`
  boot program for NFS (diskless) boot
```/usr/mdec/ufsboot`
  second-level boot program for UFS disks
```/usr/mdec/installboot`
  program to install bootxx on a disk

### SEE ALSO

disklabel(8), fsck(8), halt(8), init(8), rc(8), shutdown(8), syslogd(8)