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Windows 9X Registry
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 (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.
When a new device 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.
Improvement over INI files
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.
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 Autoexec.bat, Config.sys, and INI files, because many Win 16-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 [286Enh] section of System.ini at startup to check for virtualization drivers to ensure that they are loaded.
Network Access to Registry Information
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 the 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.
Windows Management InfrastructureThe 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.
Caution: Making a mistake in editing the registry can cause your system to become unstable and/or unusable.
Whenever possible, use the administrative tools, such as Control Panel or System Policy Editor, to make configuration changes, rather than editing the registry. This is to insure values are stored properly in the registry when changing the configuration.
If you use Registry Editor to change values, you will not be warned if any entry is incorrect. Editing the registry directly by using Registry Editor can cause errors in loading hardware and software, and can prevent users from being able to start the computer.
Dell Computer Corporation does not support editing the registry. Do not edit the registry without consulting a Technical Support Mentor and without taking into account the level of experience of the end user (customer).
Overview of the Windows 98 Registry
The structure of the Windows 98 registry has not changed significantly from the Windows 95 registry. What has changed is that code that handles the registry has become faster and more robust, and the registry now detects when certain problems arise, and automatically fixes them.
The registry is the central storage for all configuration data. The Windows 98 system configuration, the computer hardware configuration, configuration information about Win32-based applications, and user preferences are all stored in the registry. For example, any Windows 98 computer hardware configuration changes that are made with a Plug and Play device are immediately reflected in a configuration change in the registry. Because of these characteristics, the registry serves as the foundation for the user, system, and network management in Windows 98.
The registry stores the data in a hierarchical form. Because the registry contains all settings required to configure memory, hardware peripherals, and Windows 98 - supplied network components, you will find that it is no longer necessary to configure settings in startup and configuration and initialization files. Also, because all settings are stored in a central location, you can provide both local and remote support for system configuration using Windows 98 tools.
To properly manage resources, such as Interrupt requests (IRQs), I/O addresses, and direst memory access (DMAs), Windows 98 uses the registry to track devices and resources allocated for both Plug and Play-compliant devices, ACPI mechanisms, and legacy devices. The registry provides a centralized, dynamic data store for all Windows settings, with a "current configuration" branch that stores information on a per-configuration basis. For example, the Display option in Control Panel stores per-configuration information about display resolution changes and the Print option in Control Panel stores per-configuration information about the default printer.
Device Manager - which is accessed from the System option in Control Panel - provides a graphical representation of devices configured in Windows 98, and allows properties used by these devices to be viewed and changed, as appropriate. Device Manager also shows resources allocated for the configured devices. Through the resource configuration information maintained in the registry, Windows 98 is able to automatically identify and resolve device resource conflicts for Plug and Play - compliant devices. For legacy devices, Device Manager helps users quickly identify and resolve resource conflicts with devices in the system.
The registry is roughly analogous to the INI files used under Windows 3.x, with each key in the registry similar to a bracketed heading in an INI file and with registry values similar to entries under the INI headings. However, registry keys can contain subkeys, while INI files do not support nested headings. Registry values can also consist of binary data, rather that the simple strings used in INI files.
Although Microsoft discourages using INI files in favor of registry entries, some applications (particularly 16-bit, Windows-based applications) still use INI files. Windows 98 supports INI files solely for compatibility with those applications and related tools (such as setup programs). The Autoexec.bat and Config.sys also still exist for compatibility with real-mode system components and to allow users to change certain default system settings, such as the PATH environment variable. New Win32-based applications can store their initialization information in the registry.
The Windows 98 registry provides the following benefits:
Because user-specific registry information can be maintained on a central network server when user profiles are enabled, users can have access to personal desktop and network access preferences when logging on to any computer, and settings for multiple users can be maintained on a single computer. Also, system policies can be used to enforce certain registry settings for individuals, workgroups, or all users.
Overview of the Registry FilesAlthough the registry is logically one data store, physically it consists of three different files to allow maximum network configuration flexibility. Windows 98 uses the registry to store information in three major categories.
Benefits of the Registry StructureBreaking the registry into three logical components provides several benefits.
How Windows 98 Components Use the Registry
The registry contains ordered pairs of keys and their associated values that are manipulated through the Win32 registry application programming interfaces (APIs). For example, the registry might have a Wallpaper key with an associated value of Work.bmp, meaning that the current desktop background is configured to use the Work bitmap.
Additionally, a special category of keys known as dynamic keys points to either a memory location or a callback function. Dynamic keys are used by device drivers or Windows 98 subsystems that want to register a dynamic data type, such as a counter, in the registry. In the case of network cards, the dynamic keys represent data, such as data transfer rates, number of framing errors, packets dropped, and so on. In general, dynamic keys are used for reporting data, not for storage in the disk-based registry. Because the dynamic keys exist only in memory, their data can be quickly updated and accessed. The data can be accessed by the system performance tools in Windows 98, which call upon the registry for the data they are monitoring.
Keys and values can be created either programmatically or by using the Registry Editor (REGEDIT) tool. The APIs for programmatically managing the registry are the Win32 registry APIs, which can be remotely invoked by the Microsoft remote procedure call (RPC) (distributed computing environment [DCE] - compliant) support built into Windows 98. Windows 98 includes both the client and server portions of Microsoft RPC, making the registry manageable remotely from another computer running Windows 98. In this scenario, the network administrator's system is the RCP client. It accesses the registry APIs on the target computer running Windows 98 through the RPC server running on the target machine. This RPC access to the registry is secure, and network administrators can limit access to either specified privileged users or a group of network administrators.
With Windows 98, the operating system stores and checks the configuration information in the registry for most configuration settings during system startup. Windows 98 components and applications also use the registry for storing and accessing configuration information:
Overview of the Main Registry Tools
Recommended tools to modify the registryThe simplest and safest way (and the recommended way) to modify the registry is to use the tools listed:
You can also modify the registry using Registry Editor, but use it sparingly and carefully. If you use Registry Editor, always back up the registry before changing anything.