Chapter 5 -- The System Registry

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Chapter 5

Software has become more complex and also more configurable. In Microsoft Windows, that configuration can be achieved with the registry. The registry is a mechanism that makes it much easier for an application or service to maintain persistent configuration settings. The registry is a centrally located hierarchical database that offers the following capabilities:

• Although the registry is composed of multiple physical files, programmers treat it as a single database for storing and retrieving information.
• Designed in a hierarchical fashion, the registry allows an application to impose its own organization on its configuration settings.
• The registry provides support for multiple users and is essentially separated into two parts: a part for local machine settings (HKEY_LOCAL_MACHINE) and a part for user settings (HKEY_USERS).
• The registry provides security capabilities with which permissions and auditing settings can be applied to specific keys.
• The registry allows for multiple data types, including binary, DWORD, string, and multistring.

Before we jump into the details of the registry, I should discuss the two utilities available in Microsoft Windows 2000 for browsing and modifying the registry, RegEdit.exe and RegEdt32.exe. RegEdit.exe is basically the same registry utility found in Microsoft Windows 98, but it lacks features that support the security aspects of the Windows 2000 registry. RegEdt32.exe is a little less intuitive to use, but it has full support for the securing of registry keys and also provides more capabilities for manipulating registry values. For many purposes you can use either utility to browse and modify the registry, but for certain cases you will be restricted to RegEdt32.exe or some other utility.