Transcript INSTALASI WINDOWS 2000 - Gadjah Mada University

WINDOWS XP
Startup and Shutdown
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Boot Process
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Start with the installation of Windows XP and proceed
through the execution of Ntldr and Ntdetect.
Device drivers are a crucial part of the boot process, so we'll
explain the way that they control the point in the boot
process at which they load and initialize
Then we'll describe how the executive subsystems initialize
and how the kernel launches the user-mode portion of
Windows XP by starting the Session Manager process
(Smss.exe), the Win32 subsystem, and the logon process
(Winlogon).
Boot Process Components
Component
Processor
Execution
Responsibilities
Master boot record
(MBR) code
16-bit real mode
Reads and loads partition boot sectors
Boot sector
16-bit real mode
Reads the root directory to load Ntldr
Ntldr
16-bit real mode
and 32-bit
protected
mode;turns
on paging
Reads Boot.ini, presents boot menu, and
loads Ntoskrnl.exe, Bootvid.dll, Hal.dll,
and boot-start device drivers
Ntoskrnl.exe
32-bit protected
mode with
paging
Initializes executive subsystems and boot
and system-start device drivers,
prepares the system for running native
applications, and runs Smss.exe
Smss
32-bit native
application
Loads Win32 subsystem, including
Win32k.sys and Csrss.exe, and starts
Winlogon process
Winlogon
32-bit native
application
Starts the service control manager (SCM),
the Local Security Subsystem (Lsass),
and presents interactive logon dialog
box
Service control
manager (SCM)
32-bit native
application
Loads and initializes auto-start device
drivers and Win32 services
Pre Boot
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Instalation WXP on the computer
the system's primary hard disk is prepared with code that takes
part in the boot process. So what code ?
let's look at how and where Windows XP places the code on a
disk
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Since the early days of MSDOS, a standard has existed on x86
systems for the way physical hard disks are divided into volumes
Microsoft operating systems split hard disks into discrete areas
known as partitions and use file systems (such as FAT and NTFS) to
format each partition into a volume.
A hard disk can contain up to four primary partitions. Because this
apportioning scheme would limit a disk to four volumes, a special
partition type, called an extended partition, further allocates up to
four additional partitions within each primary partition.
Extended partitions can contain extended partitions, which can
contain extended partitions, and so on, making the number of
volumes an operating system can place on a disk effectively
infinite.
Continued
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Physical disks are addressed in units known as sectors. A hard disk
sector on an IBM-compatible PC is typically 512 bytes.
Utilities that prepare hard disks for the definition of logical drives,
including the MS-DOS Fdisk utility or the Windows XP Setup
program, write a sector of data called a master boot record (MBR)
to the first sector on a hard disk.
The MBR includes a fixed amount of space that contains executable
instructions (called boot code) and a table (called a partition table)
with four entries that define the locations of the primary partitions
on the disk.
When an IBM-compatible computer boots, the first code it
executes is called the BIOS, which is encoded into the
computer's ROM. The BIOS reads the MBR into memory and
transfers control to the code in the MBR.
Continued
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The MBRs written by Microsoft partitioning tools, such as the
one integrated into Windows XP Setup and the Disk
Management MMC snap-in, go through a similar process of
reading and transferring control.
First, an MBR's code scans the primary partition table
until it locates a partition containing a flag that
signals the partition is bootable.
When the MBR finds at least one such flag, it reads
the first sector from the flagged partition into
memory and transfers control to code within the
partition. This type of partition is called a boot
partition, and the first sector of such a partition is
called a boot sector.
Continued
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Operating systems generally write boot sectors to
disk without a user's involvement.
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For example, when Windows XP Setup writes the MBR to a
hard disk, it also writes a boot sector to the first bootable
partition of the disk.
You might have used the MS-DOS sys command to manually
write MS-DOS boot sectors to disks.
Windows XP Setup checks to see whether the boot
sector it will overwrite with a Windows XP boot sector
is a valid MS-DOS boot sector. If it is, Windows XP
Setup copies the boot sector's contents to a file
named Bootsect.dos in the root directory of the
partition.
Continued
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Before writing to a partition's boot sector, Windows
XP Setup ensures that the partition is formatted with
a file system that Windows XP supports (FAT, FAT32,
or NTFS) by formatting the boot partition (and any
other partition) with a file system type you specify. If
partitions are already formatted, you can instruct
Setup to skip this step.
After Setup formats the boot partition, Setup copies
the files Windows XP uses to the logical disk drive,
including two files that are part of the boot sequence,
Ntldr and Ntdetect.com.
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Another of Setup's roles is to create a boot
menu file, Boot.ini, in the root directory of the
boot partition.
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This file contains options for starting the version of
Windows XP that Setup installs and any
preexisting Windows XP installations.
If Bootsect.dos contains a valid MS-DOS boot
sector, one of the entries Boot.ini creates is to
boot into MS-DOS.
The following output shows an example Boot.ini
file from a dual-boot computer on which MS-DOS
is installed before Windows XP :
Boot.ini
[boot loader]
timeout=30
default=multi(0)disk(0)rdisk(0)partition(1)\WINNT
[operating systems] multi(0)disk(0)rdisk(0)partition(1)
\WINNT="Microsoft Windows XP Professional" /fastdetect
C:\="Microsoft Windows"
/FASTDETECT
Default boot option for Windows XP. Replaces the Windows NT 4 switch /NOSERIALMICE.
The reason the qualifier exists (vs. just having NTDETECT perform this operation by
default) is so that NTDETECT can support booting Windows NT 4. Windows XP Plug and
Play device drivers perform detection of parallel and serial devices, but Windows NT 4
expects NTDETECT to perform the detection. Thus, specifying /FASTDETECT causes
NTDETECT to skip parallel and serial deviceenumeration (actions that are not required
when booting Windows XP), whereas omitting the switch causes NTDETECT to perform
this enumeration (which isrequired for booting Windows NT 4).
The Boot Sector and Ntldr
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Setup must know the partition format before it writes a boot sector
because the contents of the boot sector vary depending on the format.
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For example, if the boot partition is a FAT partition, Windows XP writes
code to the boot sector that understands the FAT file system. But if the
partition is in NTFS format, Windows XP writes NTFS-capable code.
The role of the boot-sector code is to give Windows XP information
about the structure and format of a logical disk drive and to read in
the Ntldr file from the root directory of the logical disk drive. Thus, the
boot-sector code contains just enough read-only file system code to
accomplish this task.
After the boot-sector code loads Ntldr into memory, it transfers control
to Ntldr's entry point. If the boot-sector code can't find Ntldr in the
logical disk drive's root directory, it displays the error message "BOOT:
Couldn't find NTLDR" if the boot file system is FAT or "NTLDR is
missing" if the file system is NTFS.
Continued
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Ntldr begins its existence while a system is executing in an x86
operating mode called real mode.
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In real mode, no virtual-to-physical translation of memory
addresses occurs, which means that programs that use the
memory addresses interpret them as physical addresses and that
only the first 1 MB of the computer's physical memory is accessible.
Simple MS-DOS programs execute in a real mode environment.
However, the first action Ntldr takes is to switch the system to
protected mode. Still no virtual-to-physical translation occurs at
this point in the boot process, but a full 32 bits of memory
becomes accessible.
After the system is in protected mode, Ntldr can access all of
physical memory. After creating enough page tables to make
memory below 16 MB accessible with paging turned on, Ntldr
enables paging.
Protected mode with paging enabled is the mode in which
Windows XP executes in normal operation.
Continued
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After Ntldr enables paging, it is fully operational.
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However, it still relies on functions supplied by the boot code to
access IDE-based system and boot disks as well as the display. The
boot-code functions briefly switch off paging and switch the
processor back to a mode in which services provided by the BIOS
can be executed.
If either the boot or system drives are SCSI-based, Ntldr loads a
file named Ntbootdd.sys and uses it instead of the boot-code
functions for disk access.
Ntldr next reads the Boot.ini file from the root directory using
built-in file system code.
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Like the boot sector's code, Ntldr contains read-only NTFS and FAT
code;
unlike the boot sector's code, however, Ntldr's file system code can
read subdirectories.
Continued
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Ntldr clears the screen and if there is more than one
boot-selection entry in Boot.ini, it presents the user
with the boot-selection menu. (If there is only one
entry, Ntldr bypasses the menu and proceeds to
displaying the startup progress bar.)
Selection entries in Boot.ini direct Ntldr to the
partition on which the Windows XP system directory
(typically \Winnt) of the selected installation resides.
This partition might be the same as the boot
partition, or it might be another primary partition.
Continued
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If the Boot.ini entry refers to an MS-DOS installation
(that is, by referring to C:\ as the system partition),
Ntldr reads the contents of the Bootsect.dos file into
memory, switches back to 16-bit real mode, and calls
the MBR code in Bootsect.dos.
This action causes the Bootsect.dos code to execute
as if the MBR had read the code from disk. Code in
Bootsect.dos continues an MSDOSspecific boot, such
as is used to boot Microsoft Windows 98 or Microsoft
Windows 95 on a computer on which these operating
systems are installed with Windows XP.
Continued
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If the user doesn't select an entry from the selection menu within the
timeout period the Boot.ini file specifies, Ntldr chooses the default
selection.
Once the boot selection has been made, Ntldr loads and executes
Ntdetect.com, a 16-bit real-mode program that uses a system's BIOS
to query the computer for basic device and configuration information.
This information includes the following:
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The time and date information stored in the system's CMOS (nonvolatile
memory)
The types of buses (for example, ISA, PCI, EISA, Micro Channel Architecture
[MCA]) on the system and identifiers for devices attached to the buses
The number, size, and type of disk drives on the system
The types of mouse input devices connected to the system
The number and type of parallel ports configured on the system
This information is gathered into internal data structures that will be
stored under the HKLM\HARDWARE\DESCRIPTION registry key
later in the boot.
Continued
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Ntldr then clears the screen and displays the
"Starting Windows" progress bar. This progress bar
remains empty until Ntldr begins loading boot drivers.
(See step 5 in the following list.) Below the progress
bar is the message "For troubleshooting and
advanced startup options for Windows XP, press F8."
If the user presses F8, the advanced boot menu is
presented, which allows the user to select such
options as booting from last known good, safe mode,
debug mode, and so on.
Cotinued
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Next, Ntldr begins loading the files from the boot partition
needed to start the kernel initialization:
1. Loads the appropriate kernel and HAL images (Ntoskrnl.exe and
Hal.dll by default). If Ntldr fails to load either of these files, it prints
the message "Windows XP could not start because the following
file was missing or corrupt," followed by the name of the file.
2. Reads in the SYSTEM registry hive,
\Winnt\System32\Config\System, so that it can determine which
device drivers need to be loaded to accomplish the boot.
3. Scans the in-memory SYSTEM registry hive and locates all the boot
device drivers. Boot device drivers are drivers necessary to boot
the system. These drivers are indicated in the registry by a start
value of SERVICE_BOOT_START. Every device driver has a registry
subkey under HKLM\SYSTEM\CurrentControlSet\Services. For
example, Services has a subkey named Dmio for the Logical Disk
Manager driver, which you can see in Figure below.
Continued
4. Adds the file system driver that's responsible for implementing the code for the
type of partition (FAT, FAT32, or NTFS) on which the installation directory
resides to the list of boot drivers to load. Ntldr must load this driver at this
time; if it didn't, the kernel would require the drivers to load themselves, a
requirement that would introduce a circular dependency.
5. Loads the boot drivers. To indicate the progress of the loading, Ntldr updates a
progress bar displayed below the text "Starting Windows." The progress bar
moves for each driver loaded. (It assumes there are 80 boot device drivers—
each successful load moves the progress bar by 1.25 percent.) If the /SOS
switch is specified in the Boot.ini selection, Ntldr doesn't display the progress
bar but instead displays the filenames of each boot driver. Keep in mind that
the drivers are loaded but not initialized at this time—they initialize later in the
boot sequence.
6. Prepares CPU registers for the execution of Ntoskrnl.exe.
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This action is the end of Ntldr's role in the boot process. At this point, Ntldr
calls the main function in Ntoskrnl.exe to perform the rest of the system
initialization.
Initializing the Kernel and
Executive Subsystems
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When Ntldr calls Ntoskrnl, it passes a data structure
that contains a copy of the line in Boot.ini that
represents the selected menu option for this boot, a
pointer to the memory tables Ntldr generated to
describe the physical memory on the system, a
pointer to the in-memory copy of the HARDWARE
and SYSTEM registry hives, and a pointer to the list
of boot drivers Ntldr loaded.
Ntoskrnl then begins the first of its two-phase
initialization process, called phase 0 and phase 1.
Most executive subsystems have an initialization
function that takes a parameter that identifies which
phase is executing.
Continue
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During phase 0, interrupts are disabled.
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The purpose of this phase is to build the rudimentary
structures required to allow the services needed in phase 1
to be invoked.
Ntoskrnl's main function calls KiSystemStartup, which in turn
calls HalInitializeProcessor and KiInitializeKernel for each
CPU.
KiInitializeKernel, if running on the boot CPU, performs
systemwide kernel initialization, such as initializing internal
listheads and other data structures that all CPUs share.
Each instance of KiInitializeKernel then calls the function
responsible for orchestrating phase 0, ExpInitializeExecutive.
Continue
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ExpInitializeExecutive starts by calling the
HAL function HalInitSystem, which gives
the HAL a chance to gain system control
before Windows XP performs significant
further initialization.
One responsibility of HalInitSystem is to
prepare the system interrupt controller of
each CPU for interrupts and to configure
the interval clock timer interrupt, which is
used for CPU time accounting.
Continue
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Only on the boot processor does
ExpInitializeExecutive perform initialization other
than calling HalInitSystem.
When HalInitSystem returns control,
ExpInitializeExecutive on the boot CPU proceeds
by processing the/BURNMEMORY Boot.ini switch
(if the switch is present in the line from the
Boot.ini file that corresponds to the menu
selection the user made when choosing which
installation to boot) and discarding the amount of
memory the switch specifies.
Continue
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Next, ExpInitializeExecutive calls the phase 0 initialization routines for the memory
manager, object manager, security reference monitor, process manager, and Plug and Play
manager. These components perform the following initialization steps:
1. The memory manager constructs page tables and internal data structures that are necessary to
provide basic memory services. The memory manager also builds and reserves an area for the
system file cache and creates memory areas for the paged and nonpaged pools. The other
executive subsystems, the kernel, and the device drivers use these two memory pools for
allocating their data structures.
2. During the object manager initialization, the objects that are necessary to construct the object
manager namespace are defined so that other subsystems can insert objects into it. A handle
table is created so that resource tracking can begin.
3. The security reference monitor initializes the token type object and then uses the object to create
and prepare the first token for assignment to the initial process.
4. The process manager performs most of its initialization in phase 0, defining the process and
thread object types and setting up lists to track active processes and threads. The process
manager also creates a process object for the initial process and names it Idle. As its last step,
the process manager creates the System process and creates a system thread to execute the
routine Phase1Initialization. This thread doesn't start running right away because interrupts are
still disabled.
5. The Plug and Play manager's phase 0 initialization then takes place, which involves simply
initializing an executive resource used to synchronize bus resources.
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When control returns to the KiInitializeKernel function on each processor, control proceeds
to the Idle loop, which then causes the system thread created in step 4 of the previous
process description to begin executing phase 1.
Continue
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Phase 1 consists of the following steps :
1. HalInitSystem is called to prepare the system to accept interrupts from
devices and to enable interrupts.
2. The boot video driver (\Winnt\System32\Bootvid.dll) is called, which in turn
displays the Windows XP startup screen.
3. The power manager's initialization is called.
4. The system time is initialized (by calling HalQueryRealTimeClock) and then
stored as the time the system booted.
5. On a multiprocessor system, the remaining processors are initialized and
execution starts.
6. The progress bar is set to 5 percent.
7. The object manager creates the namespace root directory, \ObjectTypes
directory, \?? directory, and the \DosDevices link to the \?? directory.
8. The executive is called to create the executive object types, including
semaphore, mutex, event, and timer.
9. The kernel initializes scheduler (dispatcher) data structures and the system
service dispatch table.
10.The security reference monitor creates the \Security directory in the object
manager namespace and initializes auditing data structures if auditing is
enabled.
Continued
11. The progress bar is set to 10 percent.
12. The memory manager is called to create the section object and the memory
manager's system worker threads
13. National language support (NLS) tables are mapped into system space.
14. Ntdll.dll is mapped into the system address space.
15. The cache manager initializes the file system cache data structures and creates
its worker threads.
16. The configuration manager creates the \Registry key object in the object
manager namespace and copies the initial registry data passed by Ntldr into the
HARDWARE and SYSTEM hives.
17. Global file system driver data structures are initialized.
18. The Plug and Play manager calls the Plug and Play BIOS.
19. The progress bar is set to 20 percent.
20. The local procedure call (LPC) subsystem initializes the LPC port type object.
21. If the system was booted with boot logging (/BOOTLOG), the boot log file is
initialized.
22. The progress bar is set to 25 percent.
Continue
23. The I/O manager initialization now takes place. This stage is a complex phase of
system startup that accounts for 50 percent of the "progress" reported in the
progress bar. The I/O manager considers each successful driver load to be
another 2 percent of progress for the boot. (If there are more than 25 drivers to
load, the progress bar stops at 75 percent.)
The I/O manager first initializes various internal structures and creates the driver
and device object types. It then calls the Plug and Play manager, power
manager, and the HAL to begin the various stages of dynamic device
enumeration and initialization. (Because this process is complex and specific to
the I/O system) Then the Windows Management Instrumentation (WMI)
subsystem is initialized, which provides WMI support for device drivers that
adhere to the Windows Driver Model(WDM). Next, all the boot-start drivers are
called to perform their driver-specific initialization, and the system-start device
drivers are loaded and initialized. Finally, the MS-DOS device names are created
as symbolic links in the object manager's namespace.
24. The progress bar is set to 75 percent.
25. If booting in safe mode, this fact is recorded in the registry.
26. Unless explicitly disabled in the registry, paging of kernel-mode code (in Ntoskrnl
and drivers) is enabled.
Continue
27.The progress bar is set to 80 percent.
28.The power manager is called to initialize various power management structures.
29.The progress bar is set to 85 percent.
30.The security reference monitor is called to create the Command Server Thread that
communicates with Lsass.
31.The progress bar is set to 90 percent.
32.The last step is to create the Session Manager subsystem (Smss) process.Smss is
responsible for creating the user-mode environment that provides the visible interface to
Windows XP—its initialization steps are covered in the next section.
33.The progress bar is (finally) set to 100%.
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As a final step before considering the executive and kernel initialization complete, the
phase 1 initialization thread waits on the handle to the Session Manager process with a
timeout value of 5 seconds. If the Session Manager process exits before the 5 seconds
elapses, the system crashes itself with a SESSION5_INITIALIZATION_FAILED bug check
code.
If the 5-second wait times out (that is, if 5 seconds elapse), the Session Manager is
assumed to have started successfully, and the phase 1 initialization function calls the
memory manager's zero page thread function. Thus, this system thread becomes the
zero page thread for the remainder of the life of the system.
Smss, Csrss, and Winlogon
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Smss is like any other user-mode process except for two differences:
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First, Windows XP considers Smss a trusted part of the operating system.
Second, Smss is a native application. Because it's a trusted operating
system component, Smss can perform actions few other processes can
perform, such as creating security tokens.
Because it's a native application, Smss doesn't use Win32 APIs—it
uses only core executive APIs known collectively as the Windows
2000 native API. Smss doesn't use the Win32 APIs because the
Win32 subsystem isn't executing when Smss launches.
In fact, one of Smss's first tasks is to start the Win32 subsystem.
Smss then calls the configuration manager executive subsystem to
finish initializing the registry, fleshing the registry out to include all its
keys.
The configuration manager is programmed to know where the core
registry hives are stored on disk (excluding hives corresponding to
user profiles) and records the paths to the hives it loads in the
HKLM\SYSTEM\CurrentControlSet\Control\hivelist key.
Continue
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The main thread of Smss performs the following initialization steps:
1. Creates an LPC port object (\SmApiPort) and two threads to wait for client requests (such as to
load a new subsystem or create a session).
2. Defines the symbolic links for MS-DOS device names (such as COM1 and LPT1).
3. If Terminal Services is installed, creates the \Sessions directory in the object manager's namespace
(for multiple sessions).
4. Runs any programs defined in HKLM\SYSTEM\CurrentControlSet\ Control\Session
Manager\BootExecute. Typically, this value contains one command to run Autochk (the boot-time
version of Chkdsk).
5. Performs delayed file rename operations as directed by
HKLM\SYSTEM\CurrentControlSet\Control\Session Manager\PendingFileRenameOperations. Pending
file deletes are in PendingFileRenameOperations2.
6. Opens known DLLs.
7. Creates additional paging files.
8. Initializes the registry. The configuration manager fleshes out the registry by loading the registry
hives for the HKLM\SAM, HKLM\SECURITY, and HKLM\SOFTWARE keys. Although HKLM\SYSTEM\
CurrentControlSet\Control\hivelist locates the hive files on disk, the configuration manager is coded
to look for them in \Winnt\System32\Config.
9. Creates system environment variables.
10. Loads the kernel-mode part of the Win32 subsystem (Win23k.sys). Smss determines the location of
Win32k.sys and other components it loads by looking for their paths in
HKLM\SYSTEM\CurrentControlSet\Control\Session Manager. The initialization code in Win32k.sys
uses the video driver to switch the screen to the resolution defined by the default profile, so this is
the point at which the screen changes from the VGA mode the boot video driver uses to the default
resolution chosen for the system.
Continue
11. Starts the subsystem processes, including Csrss. (As noted
the POSIX and OS/2 subsystems are defined to start on
demand.)
12. Starts the logon process (Winlogon). The startup steps of
Winlogon are described shortly.
13. Creates LPC ports for debug event messages (DbgSsApiPort
and DbgUiApiPort) and threads to listen on those ports.
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After performing these initialization steps, the
main thread in Smss waits forever on the
process handles to Csrss and Winlogon.
If either of these processes terminates
unexpectedly, Smss crashes the system, since
Windows XP relies on their existence.
Continue
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Winlogon then performs its startup steps, such as creating the initial
window station and desktop objects, loading GINA DLLs, and so on. It
then creates the service control manager (SCM) process
(\Winnt\System32\Services.exe), which loads all services and device
drivers marked for auto-start, and the local security authentication
subsystem (Lsass) process (\Winnt\System32\Lsass.exe).
After the SCM initializes the auto-start services and drivers and a user
has successfully logged on at the console, the SCM deems the boot
successful. The registry last known good control set (as indicated by
HKLM\SYSTEM\Select\LastKnownGood) is updated to match
\CurrentControlSet. If a user chooses to boot to the last known good
menu during the first steps of a boot, or if a driver returns a severe or
critical error, the system uses the LastKnownGood value as the current
control set. Doing so increases the chances that the system will boot
successfully, because at least one previous boot using the last known
good profile was successful.
END OF PROCESS
That action brings us to the end
of the boot process.