.TH tboot "" "" "Technical Information"
.PC "Describe the tertiary bootstrap"
.PP
.II "tertiary booting"
.II "booting^tertiary"
.I Booting
is the process of loading \*(CO into memory and setting it into motion.
This normally occurs after you have turned on your computer.
The term comes from the old expression about pulling one's self up by one's
bootstraps.
.PP
Booting can be quite involved, and uses a number of files, depending upon
the version of \*(CO being booted and the medium from which you are
booting it.
The subject of this article,
.BR tboot ,
is the booting program that performs tertiary booting.
.PP
To grasp what is meant by ``tertiary booting'', consider how the boot sequence
works:
.IP 1. 0.3i
The BIOS loads the first 512 bytes off of the first hard disk and runs it.
This program is called the \fBmaster boot\fR.
Mark Williams Company recommends that you
use the \*(CO master boot, because it lets you boot off any partition
on either of the first two drives.
.IP 2.
The master boot loads the first 512 bytes off the active partition and runs
that.
This program is the ``secondary boot'' program.
.sp \n(pDu
The secondary boot is generally responsible for loading the operating system
off the active parition and running it.
.PP
Recent releases of \*(CO need a more sophisticated program to load
the operating system than can fit into 512 bytes.
In these releases of \*(CO,
the secondary boot loads a program off the root file system; this program is
called the ``tertiary boot'', or 
.BR tboot .
.PP
.B tboot
evaluates the hardware of your computer to provide the operating
system (\*(CO) with vital information.
This evaluation allows \*(CO
to run without modification on a wider range of hardware.
.PP
.B tboot
is responsible for loading the operating system kernel.
It first looks for a file called
.BR autoboot ,
which it then loads.
If
.B autoboot
does not exist,
.B tboot
prompts you to type in the name of a kernel, e.g.,
.B begin
(during installation) or
.BR coherent .
If you do not remember the name of the kernel you wish to
boot, you can type
.B dir
or
.B ls
for a list of files in your root file system.
.PP
Pressing the spacebar when the prompt is displayed prevents execution of
.B /autoboot
and causes
.B tboot
to pause.
You can then type the name of an alternate kernel to load (assuming it already
resides within the root directory),
type
.B ls
to see a listing of files, or type
.B info
for a display of hard-drive parameters.
.SH "See Also"
.Xr "Administering COHERENT," administe
.Xr "booting" booting
