Registry is the central storage for all configuration data of a Windows computer. It stores Windows operating system configuration, computer hardware configuration, configuration information about Win32-based applications, and user preferences in a hierarchical database file. Changes in hardware configuration and user preferences are reflected in the registry. Hence, the registry serves as a foundation for users, computers, and network management in Windows operating systems.
Pre-Windows 9x operating systems use startup configuration and initialization (INI) files for configuration settings. These INI files are not required in post-Windows 9x operating systems.
Note: For 16-bit application support, WIN.INI and SYSTEM.INI initialization files are provided with Windows operating systems.
As registry keeps all the settings at a central location, both local and remote support for system configuration can be provided using various Windows tools.
Registry Editing Utilities
Windows provides two registry editors to edit the registry entries of a Windows computer, REGEDT32.EXE and REGEDIT.EXE. Although both REGEDT32.EXE and REGEDIT.EXE are installed during the setup of Windows, the former is recommended for use. REGEDIT.EXE is not recommended because it does not have a security menu or a read-only mode.
Note:
- Windows 9x includes only REGEDIT.EXE.
- In Windows XP/2003 versions, both the tools have been merged.
Caution! Incorrect use of the registry editor can cause serious problems in a computer. Therefore, it is recommended to modify configuration settings using either the Control Panel or Administrative Tools. But if the registry editor has to be used to modify configuration settings, it is suggested to either save a backup copy or open the file in read-only mode to prevent accidental modifications in configuration data.
Other Registry Tools
Windows Registry Checker (SCANREG): SCANREG is a utility that scans an existing registry for errors. It scans the registry for errors as well as checks it for deleted but not removed entries. These entries often cause the registry to bloat, thereby deteriorating its performance. The following switches are used with the
SCANREG utility:
| Switches | Description |
| ? | Displays usage. |
| BACKUP | Backs up the registry and related system configuration files. |
| RESTORE | Chooses a backup to restore. |
| FIX | Repairs the registry. |
| COMMENT="<comment>" | Adds a specified comment to the CAB file while backing up the registry. |
Note: SCANREG is available with Windows 98 and Windows Me versions.
Registry Monitor (REGMON): REGMON is a utility for monitoring changes in registry. It displays the applications that are accessing the registry, the keys accessed by them, and the registry data that is being read and written by them, in real-time.
Note: REGMON is a third party utility available on the Web.
Registry permission modification tools
REGEDT32: REGEDT32 enables administrators to modify registry permissions. It presents the registry in five different windows corresponding to the different files that are also known as hives.
Note: REGEDIT was introduced with Windows 95. Since Windows 95 did not implement ACL security on registry keys,
REGEDIT cannot manage registry permissions.
REGMOD32: REGMOD32 modifies the permission settings of a given registry key. This was developed to help fix a limitation on the Office 95 product as installed on Windows NT. It is available only with Windows NT versions.
