<s>
The	O
Windows	O
9x	O
series	O
of	O
operating	B-General_Concept
systems	I-General_Concept
refers	O
to	O
the	O
kernel	B-Operating_System
which	O
lies	O
at	O
the	O
heart	O
of	O
Windows	O
9x	O
.	O
</s>
<s>
Its	O
architecture	O
is	O
monolithic	B-Operating_System
.	O
</s>
<s>
The	O
basic	O
code	O
is	O
similar	O
in	O
function	O
to	O
MS-DOS	B-Application
.	O
</s>
<s>
As	O
a	O
16-/32	O
-bit	O
hybrid	O
,	O
it	O
requires	O
support	O
from	O
MS-DOS	B-Application
to	O
operate	O
.	O
</s>
<s>
32-bit	O
shell	B-Operating_System
and	O
command	O
line	O
interpreter	O
:	O
</s>
<s>
ADVAPI32.DLL	O
Functionality	O
additional	O
to	O
the	O
kernel	B-Operating_System
.	O
</s>
<s>
Installable	B-Application
file	I-Application
System	I-Application
Manager	I-Application
:	O
</s>
<s>
The	O
system	O
may	O
also	O
use	O
CONFIG.SYS	B-Device
,	O
which	O
contains	O
settings	O
and	O
commands	O
executed	O
before	O
loading	O
the	O
command	O
interpreter	O
)	O
and	O
AUTOEXEC.BAT	O
,	O
which	O
is	O
a	O
batch	O
file	O
automatically	O
executed	O
after	O
loading	O
COMMAND.COM	B-Operating_System
.	O
</s>
<s>
However	O
,	O
these	O
two	O
files	O
are	O
not	O
critical	O
to	O
the	O
boot	B-Operating_System
process	I-Operating_System
,	O
as	O
IO.SYS	O
contains	O
a	O
default	O
setting	O
for	O
both	O
,	O
in	O
case	O
of	O
absence	O
from	O
the	O
system	O
.	O
</s>
<s>
In	O
Windows	B-Device
ME	I-Device
,	O
CONFIG.SYS	B-Device
and	O
AUTOEXEC.BAT	O
are	O
not	O
processed	O
and	O
LOGO.SYS	O
may	O
be	O
used	O
as	O
a	O
splash	O
screen	O
.	O
</s>
<s>
The	O
first	O
two	O
of	O
these	O
steps	O
are	O
common	O
to	O
any	O
operating	B-General_Concept
system	I-General_Concept
booting	B-Operating_System
using	O
the	O
traditional	O
combination	O
of	O
BIOS	B-Operating_System
and	O
Master	B-Device
Boot	I-Device
Record	I-Device
.	O
</s>
<s>
The	O
ROM	B-Operating_System
BIOS	I-Operating_System
starts	O
the	O
execution	O
at	O
the	O
physical	O
memory	O
address	O
FFFF0h	O
.	O
</s>
<s>
During	O
this	O
phase	O
,	O
BIOS	B-Operating_System
first	O
executes	O
the	O
Power-on	B-Device
self-test	I-Device
,	O
then	O
checks	O
for	O
the	O
existence	O
of	O
a	O
boot	B-Operating_System
disk	O
on	O
drive	O
A	O
.	O
</s>
<s>
If	O
it	O
is	O
not	O
found	O
in	O
drive	O
A	O
,	O
the	O
ROM	B-Operating_System
BIOS	I-Operating_System
checks	O
for	O
a	O
hard	O
disk	O
.	O
</s>
<s>
If	O
the	O
computer	O
has	O
a	O
Plug	B-Device
and	I-Device
Play	I-Device
BIOS	B-Operating_System
,	O
in	O
addition	O
,	O
BIOS	B-Operating_System
checks	O
the	O
RAM	O
for	O
I/O	B-General_Concept
port	O
addresses	O
,	O
interrupt	O
lines	O
and	O
DMA	O
channels	O
for	O
Plug	B-Device
and	I-Device
Play	I-Device
devices	O
,	O
disables	O
found	O
devices	O
,	O
creates	O
maps	O
of	O
used	O
and	O
unused	O
resources	O
and	O
re-enables	O
devices	O
.	O
</s>
<s>
The	O
Master	B-Device
boot	I-Device
record	I-Device
is	O
loaded	O
at	O
address	O
7C00h	O
and	O
loads	O
the	O
boot	B-Device
sector	I-Device
of	O
the	O
Windows	O
Disk	B-Application
partition	I-Application
.	O
</s>
<s>
The	O
boot	B-Device
sector	I-Device
contains	O
the	O
disk	O
boot	B-Operating_System
program	I-Operating_System
and	O
BIOS	B-Device
Parameter	I-Device
Block	I-Device
table	O
which	O
searches	O
for	O
the	O
location	O
of	O
the	O
root	O
directory	O
and	O
IO.SYS	O
file	O
,	O
which	O
then	O
loads	O
the	O
IO.SYS	O
file	O
into	O
memory	O
.	O
</s>
<s>
IO.SYS	O
initializes	O
the	O
minimal	O
File	B-Application
Allocation	I-Application
Table	I-Application
driver	O
and	O
loads	O
MSDOS.SYS	O
into	O
memory	O
.	O
</s>
<s>
It	O
then	O
displays	O
"	O
Starting	O
Windows	O
"	O
depending	O
on	O
the	O
Boot-Delay	O
line	O
in	O
the	O
MSDOS.SYS	O
file	O
.	O
</s>
<s>
If	O
the	O
DRVSPACE.INI	B-Device
or	O
DBLSPACE.INI	B-Device
file	O
exists	O
,	O
it	O
also	O
loads	O
drivers	O
for	O
compressed	O
disks	O
.	O
</s>
<s>
If	O
configured	O
in	O
MSDOS.SYS	O
or	O
in	O
the	O
registry	O
,	O
double	O
buffering	O
is	O
also	O
enabled	O
.	O
</s>
<s>
Windows	O
95	O
to	O
Windows	O
98	O
now	O
analyze	O
CONFIG.SYS	B-Device
and	O
load	O
MS-DOS	B-Application
real	B-Application
mode	I-Application
drivers	O
.	O
</s>
<s>
Windows	B-Device
ME	I-Device
ignores	O
this	O
.	O
</s>
<s>
If	O
the	O
CONFIG.SYS	B-Device
file	O
does	O
not	O
exist	O
,	O
the	O
IO.SYS	O
file	O
loads	O
the	O
drivers	O
IFSHLP.SYS	B-Application
,	O
HIMEM.SYS	O
and	O
SETVER.EXE	O
.	O
</s>
<s>
Windows	O
reserves	O
all	O
upper	B-Device
memory	I-Device
blocks	I-Device
for	O
Windows	O
95	O
operating	B-General_Concept
system	I-General_Concept
use	O
or	O
for	O
expanded	B-Device
memory	I-Device
.	O
</s>
<s>
Windows	O
95	O
to	O
Windows	O
98	O
execute	O
COMMAND.COM	B-Operating_System
to	O
process	O
AUTOEXEC.BAT	O
.	O
</s>
<s>
Windows	B-Device
ME	I-Device
ignores	O
this	O
step	O
,	O
as	O
Real	B-Application
Mode	I-Application
DOS	O
support	O
is	O
disabled	O
and	O
TSRs	O
being	O
loaded	O
can	O
compromise	O
system	O
stability	O
.	O
</s>
<s>
This	O
file	O
contains	O
the	O
most	O
important	O
drivers	O
and	O
the	O
9x	O
kernel	B-Operating_System
.	O
</s>
<s>
The	O
real-mode	B-Application
virtual	O
device	O
driver	O
loader	O
checks	O
for	O
duplicate	O
virtual	O
device	O
drivers	O
that	O
exist	O
both	O
in	O
the	O
Windows	O
\System\Vmm32	O
folder	O
and	O
the	O
VMM32.VXD	O
file	O
.	O
</s>
<s>
Windows	O
95	O
to	O
98	O
now	O
query	O
real	B-Application
mode	I-Application
drivers	O
calling	O
INT	O
2Fh	O
and	O
search	O
for	O
drivers	O
in	O
registry	O
entry	O
HKEY_LOCAL_MACHINE	O
\System\CurrentControlSet\Services\VxD	O
marked	O
to	O
be	O
loaded	O
as	O
an	O
external	O
file	O
.	O
</s>
<s>
Vmm32	O
then	O
analyzes	O
the	O
[	O
386	O
Enh ]	O
section	O
of	O
the	O
Windows	O
\System.ini	O
file	O
and	O
loads	O
drivers	O
listed	O
there	O
.	O
</s>
<s>
Some	O
important	O
drivers	O
are	O
loaded	O
even	O
if	O
they	O
are	O
not	O
listed	O
in	O
the	O
Windows	B-Protocol
Registry	I-Protocol
,	O
SYSTEM.INI	B-Protocol
or	O
in	O
the	O
Windows	O
\System\Vmm32	O
directory	O
.	O
</s>
<s>
Once	O
the	O
real-mode	B-Application
virtual	O
device	O
drivers	O
are	O
loaded	O
,	O
driver	O
initialization	O
on	O
Windows	O
95	O
to	O
Windows	O
98	O
occurs	O
.	O
</s>
<s>
Vmm32	O
then	O
switches	O
the	O
CPU	O
from	O
real	B-Application
mode	I-Application
to	O
protected	B-Application
mode	I-Application
.	O
</s>
<s>
The	O
next	O
step	O
is	O
the	O
initialization	O
of	O
protected	B-Application
mode	I-Application
drivers	O
,	O
executed	O
in	O
three	O
phases	O
for	O
each	O
device	O
:	O
a	O
critical	O
part	O
of	O
initialization	O
(	O
while	O
interrupts	O
are	O
disabled	O
)	O
,	O
device	O
initialization	O
(	O
when	O
file	O
I/O	B-General_Concept
is	O
allowed	O
)	O
and	O
InitComplete	O
phase	O
.	O
</s>
<s>
Once	O
all	O
of	O
the	O
drivers	O
are	O
loaded	O
,	O
the	O
Kernel32.dll	O
,	O
gdi32.dll	B-Operating_System
,	O
Gdi.exe	O
,	O
user32.dll	O
,	O
User.exe	O
,	O
shell32.dll	O
and	O
Explorer.exe	B-Protocol
files	O
are	O
loaded	O
.	O
</s>
<s>
The	O
next	O
step	O
in	O
the	O
startup	O
process	O
is	O
to	O
load	O
the	O
network	B-Architecture
environment	O
.	O
</s>
<s>
The	O
user	O
is	O
prompted	O
to	O
log	O
on	O
to	O
the	O
network	B-Architecture
that	O
is	O
configured	O
.	O
</s>
<s>
Windows	O
then	O
starts	O
programs	O
defined	O
in	O
the	O
StartUp	O
folder	O
,	O
WIN.INI	B-Protocol
and	O
programs	O
defined	O
in	O
registry	B-Protocol
keys	I-Protocol
Run	O
,	O
RunOnce	O
,	O
RunServices	O
and	O
RunServicesOnce	O
inside	O
the	O
branches	O
HKEY_LOCAL_MACHINE	O
\Software\Microsoft\Windows\CurrentVersion	O
and	O
HKEY_CURRENT_USER	O
\Software\Microsoft\Windows\CurrentVersion\	O
.	O
</s>
<s>
After	O
each	O
program	O
in	O
the	O
RunOnce	O
registry	B-Protocol
key	I-Protocol
is	O
started	O
,	O
the	O
program	O
is	O
removed	O
from	O
the	O
key	O
.	O
</s>
<s>
The	O
Windows	O
9x	O
kernel	B-Operating_System
is	O
a	O
32-bit	O
kernel	B-Operating_System
with	O
virtual	B-Architecture
memory	I-Architecture
.	O
</s>
<s>
Drivers	O
are	O
provided	O
by	O
.VXD	O
files	O
or	O
,	O
since	O
Windows	O
98	O
,	O
the	O
newer	O
WDM	B-Application
drivers	O
can	O
be	O
used	O
.	O
</s>
<s>
However	O
,	O
the	O
MS-DOS	B-Application
kernel	B-Operating_System
stays	O
resident	O
in	O
memory	O
.	O
</s>
<s>
Windows	O
will	O
use	O
the	O
old	O
MS-DOS	B-Application
16-bit	O
drivers	O
if	O
they	O
are	O
installed	O
,	O
except	O
on	O
Windows	B-Device
Me	I-Device
.	O
</s>
<s>
In	O
Windows	B-Device
Me	I-Device
,	O
DOS	O
is	O
still	O
running	O
,	O
but	O
Windows	O
will	O
ignore	O
any	O
attempt	O
to	O
load	O
its	O
device	O
drivers	O
when	O
parsing	O
the	O
AUTOEXEC.BAT	O
,	O
and	O
will	O
move	O
the	O
environment	O
variables	O
that	O
it	O
still	O
recognizes	O
from	O
the	O
CONFIG.SYS	B-Device
into	O
the	O
Windows	B-Protocol
Registry	I-Protocol
.	O
</s>
