boot -- Driver

Boot block for hard-disk partition/nine-sector diskette

Several different programs are used to  load COHERENT from a floppy or hard
disk  into memory.   This  process is  called bootstrapping  (from the  old
expression about pulling one's self  up by one's bootstraps) or booting for
short.  The program used depends  upon whether one is loading COHERENT from
a hard-disk  partition, from  a 5.25-inch floppy  disk, or from  a 3.5-inch
floppy disk.  All of these programs are installed onto your computer during
normal installation.

mboot is the  master boot program.  This is code  that resides in the first
446 bytes of  the first sector on the hard  disk.  Because this sector also
contains the  partition table for the hard disk,  mboot is normally written
to the hard drive only during installation and only by the fdisk utility.

boot,  boot.fha, and  boot.fva are  variations of  the same  program.  boot
occupies the  first sector of any  bootable hard-drive partition.  boot.fha
occupies  the  first  sector  of  a  5.25-inch, high-density  floppy  disk.
boot.fva occupies the first sector of a 3.5-inch, high-density floppy disk.

boot  is  normally  copied  to  the  root  partition  automatically  during
installation by a command such as:

    /bin/dd if=/conf/boot of=/dev/at0a count=1

In another example, the following  commands format and create a file system
on a high-density, 5.25-inch floppy disk:

    /etc/fdformat -v /dev/fha0
    /etc/mkfs /dev/fha0 2400
    /bin/cp /conf/boot.fha /dev/fha0

When  invoked, boot  loads for  the tertiary boot  program tboot.  This, in
turn,  searches the  root directory  `/'  for file  autoboot, which  is the
COHERENT  kernel.  If  it finds  this  kernel, boot  loads and  invokes it.
Otherwise,  it gives  the  prompt ?,  and  you must  type the  name of  the
operating-system kernel to  load (typically, ``coherent'').  If boot cannot
find the  requested kernel or  if an error  occurs, boot does  not print an
error message, but re-prompts with `?'.

Files

/conf/boot -- Boot for AT partitions
/conf/boot.at -- Boot for AT partitions (linked to /conf/boot)
/conf/boot.atx -- AT master boot (linked to /conf/mboot)
/conf/boot.f9a  -- Boot for  single-density, nine-sector,  5.25-inch floppy
disk
/conf/boot.fha -- Boot for 15-sector, 5.25-inch floppy disk
/conf/boot.fqa -- Boot for quad-density, nine-sector, 3.5-inch floppy disk
/conf/boot.fva -- Boot for 18-sector, 3.5-inch floppy disk
/conf/mboot -- AT master boot

See Also

device drivers,
fdisk,
mboot,
mkfs,
tboot

© 2012 by Stephen A. Ness