The windows Registry is a type of database comprising of all Windows settings and installed applications. It stores options and settings for the Microsoft Windows operating system. The registry consists of hardware settings and information, software for the operating system, most of the non operating system software, and a wide range of user settings.
The registry is also able to offer a window in the operation of kernel, exposing the runtime information such as performance counters and hardware that is currently active. When it was introduced for the first time with Windows 3.1, the computer windows registry was meant to tidy up profusion of each of the program INI files, which was previously used for the storage of configuration settings meant for various Windows programs. These files tended to scatter in the entire system, and this made tracing them very difficult. The registry can be stored in various locations in the system; in Windows ME, 98 and 95. The Registry is stored in two separate files that are hidden in the Window directory know as SYSTEM.DAT and USER.DAT. On the other hand, in Windows XP and Windows 2000, the registry is contained in many Hives that are located in \windows \system 32\ config and \documents and settings username folders.
The registry exhibits itself in a hierarchal structure, such as the directories on the hard disk. Each of the branches normally denoted by the folder icon found in Registry Editor also known as key. Each of the keys is able to contain other keys and values. For every value, there is actual information that is normally stored on the Registry. There are three different types of values available including DWORD that depends entirely on the context for it to be used, binary and string. Six main branches are known to exist with five being found in the Windows XP and Windows 2000. Each of these branches contains a specific portion of information that will eventually be stored in the registry.
The branches are ;HKEY_CLASSES_ROOT that contains all file types including OLE information for the OLE applications ,HKEY_CURRENT_USERS, show part of HKEY_USERS that are best for the person using it currently, HKEY_DYN_DATA found in Windows 98,ME and 95 shows part of HKEY_LOCAL_MACHINE for Windows Plug and Play subsystems. The HKEY_USERS branch contains specific preferences like the control panel settings and colors for any of the computer users. HKEY_LOCAL_MACHINE has information about all installed software and hardware in the computer and finally the HKEY_CURRENT_CONFIG which contains HKEY_LOCAL_MACHINE for the hardware configuration. Generally, the registry constitutes of a wide range of information for hardware and software based settings which are critical for excellent execution of installed programs and the operating system.