init and initab

i went to yaghmour's book and he discusses sysvinit on page 191
and points to an only article by Alessandro Rubini.

the highlights of what rubini states "almost anything can be used as init."
that is a shell scrip but goes to says the real init is sysvinit.
and from there there are a multitude of ways to handle the startup.

--------------------------inittab script--------------------------
# /etc/inittab: init(8) configuration.
# $Id: inittab,v 1.8 1998/05/10 10:37:50 miquels Exp $

# The default runlevel.
id:2:initdefault:

# Boot-time system configuration/initialization script.
# This is run first except when booting in emergency (-b) mode.
si::sysinit:/etc/init.d/rcS

# What to do in single-user mode.
~~:S:wait:/sbin/sulogin

# /etc/init.d executes the S and K scripts upon change
# of runlevel.
#
# Runlevel 0 is halt.
# Runlevel 1 is single-user.
# Runlevels 2-5 are multi-user.
# Runlevel 6 is reboot.

l0:0:wait:/etc/init.d/rc 0
l1:1:wait:/etc/init.d/rc 1
l2:2:wait:/etc/init.d/rc 2
l3:3:wait:/etc/init.d/rc 3
l4:4:wait:/etc/init.d/rc 4
l5:5:wait:/etc/init.d/rc 5
l6:6:wait:/etc/init.d/rc 6
# Normally not reached, but fallthrough in case of emergency.
z6:6:respawn:/sbin/sulogin

# What to do when CTRL-ALT-DEL is pressed.
ca:12345:ctrlaltdel:/sbin/shutdown -t1 -a -r now

# Action on special keypress (ALT-UpArrow).
kb::kbrequest:/bin/echo "Keyboard Request--edit /etc/inittab to let this work."

# What to do when the power fails/returns.
pf::powerwait:/etc/init.d/powerfail start
pn::powerfailnow:/etc/init.d/powerfail now
po::powerokwait:/etc/init.d/powerfail stop

# /sbin/getty invocations for the runlevels.
#
# The "id" field MUST be the same as the last
# characters of the device (after "tty").
#
# Format:
# :::
1:2345:respawn:/sbin/getty 38400 tty1
2:23:respawn:/sbin/getty 38400 tty2
3:23:respawn:/sbin/getty 38400 tty3
4:23:respawn:/sbin/getty 38400 tty4
5:23:respawn:/sbin/getty 38400 tty5
6:23:respawn:/sbin/getty 38400 tty6

# Example how to put a getty on a serial line (for a terminal)
#
#T0:23:respawn:/sbin/getty -L ttyS0 9600 vt100
#T1:23:respawn:/sbin/getty -L ttyS1 9600 vt100

# Example how to put a getty on a modem line.
#
#T3:23:respawn:/sbin/mgetty -x0 -s 57600 ttyS3

--------------------------end inittab script----------------------

first this is directly from the man page.

ok here is a step by step disection of the inittab file.
1)
The inittab file describes which processes are started at bootup and
during normal operation (e.g. /etc/init.d/boot, /etc/init.d/rc, get-
tys...). Init(8) distinguishes multiple runlevels, each of which can
have its own set of processes that are started. Valid runlevels are
0-6 plus A, B, and C for ondemand entries.
An entry in the inittab file has the following format:

id:runlevels:action:process

so the entry id:2:initdefault:

so the means the default runlevel is 2.

after reading the inittab man page i see that the file
i have is almost the same as the example shown
on the man page.

it might be for the best to use a debian system starup but
trimmed down. i could then use the scripts an documentation
that comes for debian ... i eventually want to use xwindows.

the need for init means a couple of things.
1) i need to be able to login. this means what?
passwords?
from a naive understanding