首先强调以下，注册表（registry）是Windows系统特有的，其他系统没有。
解释：
The registry is a hierarchical database that stores low-level settings for the Microsoft Windows operating system and for applications that opt to use the registry. The kernel, device drivers, services, Security Accounts Manager (SAM), and user interface can all use the registry. The registry also allows access to counters for profiling system performance.
In simple terms, the registry or Windows Registry contains information, settings, options, and other values for programs and hardware installed on all versions of Microsoft Windows operating systems. For example, when a program is installed, a new subkey containing settings such as a program's location, its version, and how to start the program, are all added to the Windows Registry.
When introduced with Windows 3.1, the Windows Registry primarily stored configuration information for COM-based components. Windows 95 and Windows NT extended its use to rationalise and centralise the information in the profusion of INI files, which held the configurations for individual programs, and were stored at various locations.
简单来说，注册表是一个数据库，用来存储程序的配置信息，例如位置、版本以及如何启动程序，它最早是在Windows3.1里被引入的。
参考来源：维基百科