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- DOCUMENT:Q100010 27-SEP-1993 [W_NT]
- TITLE :What are Control Sets? What is CurrentControlSet?
- PRODUCT :Windows NT
- PROD/VER:3.10
- OPER/SYS:WINDOWS
- KEYWORDS:
-
- ------------------------------------------------------------------
- The information in this article applies to:
-
- - Microsoft Windows NT operating system version 3.1
- ------------------------------------------------------------------
-
- WARNING: Using Registry Editor incorrectly can cause
- serious, system-wide problems that may require you to
- reinstall Windows NT to correct them. Microsoft cannot
- guarantee that any problems resulting from the use of
- Registry Editor can be solved. Use this tool at your own
- risk.
-
- A control set contains system configuration information such as device
- drivers and services. You may notice several instances of control sets
- when viewing the Registry. Some are duplicates or mirror images of
- others and some are unique. This article describes how to find control
- sets, which ones are important, and why.
-
- Control sets are stored in the HKEY_LOCAL_MACHINE hive, under the
- SYSTEM key. There may be several control sets depending on how often
- you change system settings or have problems with the settings you
- choose. A typical installation of Windows NT will contain four:
-
- \ControlSet001
- \ControlSet002
- \CurrentControlSet
- \Clone
-
- ControlSet001 may be the last control set you booted with, while
- ControlSet002 could be what is known as the last known good control
- set, or the control set that last successfully booted Windows NT. The
- CurrentControlSet subkey is really a pointer to one of the
- ControlSetXXX keys. Clone is a clone of CurrentControlSet, and is
- created each time you boot your computer by the kernel initialization
- process. In order to better understand how these control sets are
- used, you need to be aware of another subkey, Select.
-
- Select is also under the SYSTEM key. Select contains the following
- values:
-
- Current
- Default
- Failed
- LastKnownGood
-
- Each of these values contain a REG_DWORD data type and refer to
- specifically to a control set. For example, if the Current value is
- set to 0x1, then CurrentControlSet is pointing to ControlSet001.
- Similarly, if LastKnownGood is set to 0x2, then the last known good
- control set is ControlSet002. The Default value usually agrees with
- Current, and Failed refers to a control set that was unable to boot
- Windows NT successfully.
-
- The most valuable and reliable control set is CurrentControlSet. If
- you need to modify system settings in the Registry, CurrentControlSet
- is the best subkey to choose because you know that it is the correct
- control set. You also know that if your modifications harm your system
- configuration, you will still be able to boot using the last known
- good control set.
-
- If you are not sure where to look under the control set for a
- particular parameter, you can use the Find Key option under the View
- menu of Registry Editor. Each control set contains two subkeys:
- Control and Services. Control contains miscellaneous system
- information such as the size and location of the paging file. Services
- contains device driver information such as file system drivers, kernel
- drives, and status information for each.
-
- Additional reference words: 3.1
- KBCategory:
- KBSubCategory: DEVDRVR
-
- =============================================================================
-
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-
- Copyright Microsoft Corporation 1993.