Archive for May 22, 2010

What Happens When You Start Your Computer

Posted: May 22, 2010 in Bios, System Basics, System Information
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As stated earlier in this chapter, the Windows XP/Windows Server 2003 boot sequence closely resembles that of Windows NT/2000. Listed below are the processes that take place when Windows NT-based operating system successfully starts on an x86-based computer:

  • Power On Self Test (POST)
  • Initial startup process
  • Boot loader process
  • Operating-system selection (if you have a multi-boot system)
  • Hardware detection
  • Hardware-profile selection
  • Kernel-loading process
  • Kernel-initialization process
  • User-logon process
Note The startup sequence quoted above applies to systems started or restarted after a normal shutdown. The startup processes begin when you do one of the following:

  • Turn on the computer
  • Reboot the system

However, this startup sequence does not apply when resuming from hibernate or standby modes.

When you log on, the process of loading Windows NT/2000, Windows XP, or Windows Server 2003 is completed, as well as are most of the initialization procedures. However, the startup can only really be considered as successfully completed after you log on to the system.

The following requirements need to be met to successfully begin the Windows NT/2000/XP/Windows Server 2003 startup:

  • Correct initialization of all the hardware.
  • Presence of all required files for starting the OS. If any of these files aren’t present in the correct folder or are corrupt, the startup will fail.
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Registry Keys Intended for Power Management

Posted: May 22, 2010 in Registry, Server 2003, Server 2008, System Information, Vista, Windows 7, Windows XP
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In this section, we’ll discuss the registry keys that are used for power management. You may edit any of them using one of the registry editors.

Note Changing registry entries responsible for power management won’t have an immediate effect. Windows only reads settings from the registry when you log on, when you click OK in Control Panel, or when a Powerprof.dll function is called on to read the registry.

The registry keys used for power management are listed below.

  • HKCU\AppEvents\EventLabels\LowBatteryAlarm – descriptive name of a low battery-power-alarm event
  • HKCU\AppEvents\EventLabels\CriticalBatteryAlarm – descriptive name of a critical battery-power-alarm event
  • HKCU\AppEvents\Schemes\Apps\PowerCfg\LowBatteryAlarm\.Current, HKCU\AppEvents\Schemes\Apps\PowerCfg\LowBatteryAlarm\.Default, HKCU\AppEvents\Schemes\Apps\PowerCfg\CriticalBatteryAlarm\.Current, HKCU\AppEvents\Schemes\Apps\PowerCfg\CriticalBatteryAlarm\.Default – filenames of the WAV files that will play as a low and critical power-alarm events
  • HKCU\Control Panel\PowerCfg\CurrentPowerPolicy – index of current user and machine power policy
  • HKCU\Control Panel\PowerCfg\GlobalPowerPolicy\Policies – the user global power policy (binary encoded data)
  • HKCU\Control Panel\PowerCfg\PowerPolicies\n\Name – name of power scheme n, where n = 0, 1, 2, etc.
  • HKCU\Control Panel\PowerCfg\PowerPolicies\n\Description – descriptive string for power scheme n, where n = 0, 1, 2, etc.
  • HKCU\Control Panel\PowerCfg\PowerPolicies\n\Policies – user power policy n, where n = 0, 1, 2, etc. (binary encoded data)
  • HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Controls Folder\PowerCfg\LastID – index of the last power policy in the lists of user and machine power policies (for example, if there are six user power policies and six machine power policies in the registry, the value of this key is 5)
  • HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Controls Folder\PowerCfg\DiskSpinDownMax – the maximum disk spin-down time that Control Panel will allow the user to set
  • HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Controls Folder\PowerCfg\DiskSpinDownMin – the minimum disk spin-down time that Control Panel will allow the user to set
  • HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Controls Folder\PowerCfg\GlobalPowerPolicy\Policies – the machine global power policy (binary encoded data)
  • HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Controls Folder\PowerCfg\PowerPolicies\n\Policies – machine power policy n, where n = 0, 1, 2, etc. (binary encoded data)

Power Schemes Configuration in Registry

Posted: May 22, 2010 in Registry, Server 2003, System Information, Windows 7, Windows XP
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Power management configuration in Windows 2000, Windows XP, and Windows Server 2003 is based on the concept of power schemes. A power scheme is a group of preset power options that are passed to the Power Policy Manager component of the operating system to control the machine’s power-management behavior.

Each power scheme consists of a global power-policy structure and a power-policy structure.

  • Global power-policy structures contain preset power options that are global across all power schemes.
  • Non-global power-policy structures contain power options that are unique to a particular power scheme.

These power-policy structures are further divided into machine structures and user structures.

  • Values in machine structures are stored in the HKEY_LOCAL_MACHINE registry key, and none of these values are exposed in the user interface. For example, you can’t set any of these values using the Power Options applet in the Control Panel.
  • Values in user structures are stored in the HKEY_CURRENT_USER registry key and some of these values are displayed in the user interface. Some of these parameters can be set using the Power Options applet in Control Panel.

The data structures defining power management policy are listed below:

  • GLOBAL_POWER_POLICY – used to manage global power policies. This structure contains the data common to all power schemes. This structure is a container for a GLOBAL_USER_POWER_POLICY structure and a GLOBAL_MACHINE_POWER_POLICY structure, which contains elements that are read from and written to the registry.
  • GLOBAL_MACHINE_POWER_POLICY – this structure is a part of the GLOBAL_POWER_POLICY structure. It contains the data common to all power schemes and users. The elements in this structure are read from and written to the HKLM key in the registry.
  • GLOBAL_USER_POWER_POLICY – this structure is a part of the GLOBAL_POWER_POLICY structure. It contains the data common to all power schemes for the user. The elements in this structure are read from and written to the HKCU key in the registry.
  • POWER_POLICY – used to manage non-global power policies. This structure contains the data unique for all power schemes. This structure is a container for the USER_POWER_POLICY and MACHINE_POWER_POLICY structures that contain the elements to be read from and written to the registry. There is one POWER_POLICY structure for each power scheme on a machine.
  • MACHINE_POWER_POLICY – this structure is a part of the POWER_POLICY structure. It contains the data unique to each power scheme, but common to all users. The elements in this structure are read from and written to the HKLM key in the registry.
  • USER_POWER_POLICY – this structure is a part of the POWER_POLICY structure. It contains the data unique to each user and power scheme. The elements in this structure are read from and written to the HKCU key in the registry.