The central information database for Windows 98 is called the registry. This hierarchical database both simplifies the operating system and makes it more adaptable. The registry simplifies the operating system by eliminating the need for Autoexec.bat, Config.sys, and INI files, however, Windows 98 still supports the use of these files when legacy applications require them. It makes the operating system more adaptable by storing user-specific and configuration-specific information so you can share one computer among multiple users and have more than one configuration (such as in-the-office and on-the-road configurations) for each computer.
A primary role of the registry in Windows 98 is to serve as a central repository for hardware-specific information for use by the hardware detection and Plug and Play system components. Windows 98 maintains information about hardware components and devices that have been identified through an enumeration or detection process, in the hierarchical structure of the registry, as described in "Configuration Manager" later in this chapter. When a new device is installed, the system checks for an existing configuration in the registry. If none is found, Windows 98 then searches all available media for the driver that best matches the device. Once the driver is found, it is added to the registry alongside the settings for the device.
Earlier versions of Windows used initialization (INI) files to store system-specific or application-specific information on the state or configuration of the system. For example, the Win.ini file stored information about the appearance of the Windows environment, the System.ini file stored system-specific information on the hardware and device driver configuration of the system, and various INI files (such as Msmail.ini and Winword6.ini) stored application-specific information.
The registry alleviates the issues of dealing with multiple INI files by providing a single location for the computer’s configuration information. Table 28.1 illustrates other issues or limitations using multiple INI files, along with the solutions that are provided by using the registry.
Table 28.1 Registry solutions for problems with INI files
Problem | Solution |
---|---|
INI files are text-based, limited to 64 KB in total size. | The registry has no size restriction and can include both binary and text values. |
Information stored in INI files is nonhierarchical and supports only two levels of information. | The registry is hierarchically arranged. |
Many INI files contain a myriad of switches and entries that are complicated to configure or are used only by operating system components. | The registry contains more standardized values. |
INI files provide no mechanism for storing user-specific information, thus making it difficult for multiple users to share a single computer or for users who move around on the network to have access to their user-specific settings. | The HKEY_USERS key stores user-specific information. |
Configuration information in INI files is local to each system, and no API mechanisms are available for remotely managing configuration, thus making it difficult to manage multiple computers. | The registry can be remotely administered, and system policies (stored as registry values) can be downloaded from a central server each time a new user logs on. For more information, see Chapter 7, "User Profiles," Chapter 8, "System Policies," and Chapter 23, "System and Remote Administration Tools." |
When you upgrade from Windows 3.1 to Windows 98, system-specific information, such as the references to the loading of static virtualization drivers (VxDs), is moved (as appropriate) from the System.ini file to the registry.
For backward compatibility, Windows 98 supports the Autoexec.bat, Config.sys, and INI files, because many Win16-based applications still use them. For example, Windows 98 allows Win16-based applications to use INI files for their program settings, parameters, device drivers, and so on that the applications need to run. In addition, Windows 98 continues to scan the [386Enh] section of System.ini at startup to check for virtualization drivers to ensure that they are loaded.
One advantage of the registry for Win32-based applications is that many of the Win32-based registry APIs can be used remotely through the remote procedure call (RPC) mechanism in Windows 98 to provide access to registry information across a network. This means that network administrators can use system management tools to access the contents of the registry for any computer on the network. (Of course, the remote computer must be configured to allow remote administration and must have user-level security.)
With Windows 98 remote administration, such industry management mechanisms as Simple Network Management Protocol (SNMP) can easily be integrated into Windows 98, lightening the network administrator’s management and support burden. For more information, see Chapter 23, "System and Remote Administration Tools."
The Windows Management Infrastructure collects a wealth of information about the entire system as well as device configuration. This information is stored in the registry and made available through extensions to the registry API. This software is the foundation of Microsoft’s support for Desktop Management Interface (DMI) and will provide device and system information to OLE Management Services (OLE MS) and Simple Network Management Protocol (SNMP) in the future.
For more information about the registry, see Chapter 31, "Windows 98 Registry."