What is the Registry?

The Windows operating system has different levels of components, and parts. One such component is the registry, which is a hierarchal database that stores different configuration settings for ini files, which are program settings in text files. The registry works mainly with low level components. The term “low level” refers to components that communicate closely with the hardware. The registry is an important part of the operating system and contains settings for components and programs such as the kernel, device drivers, services, SAM, user interface and most third party applications. The registry is a little different than any other components you might encounter because it uses keys and values. There is a basic hierarchy of keys and at the end of the hierarchical tree there are the values. These values are settings, and most are either in hexadecimal or binary form. The keys themselves use backslashes to indicate levels in hierarchy.

There are seven predefined root keys, and are called Hives. These hives are:
• HKEY_LOCAL_MACHINE or HKLM
• HKEY_CURRENT_CONFIG or HKCC (only in Windows 9x/ME and NT-based versions of Windows)
• HKEY_CLASSES_ROOT or HKCR
• HKEY_CURRENT_USER or HKCU
• HKEY_USERS or HKU
• HKEY_PERFORMANCE_DATA (only in NT-based versions of Windows, but invisible in the Windows Registry Editor)
• HKEY_DYN_DATA (only in Windows 9x/ME, and visible in the Windows Registry Editor)

Since this is a very important area of the computer, only users with specific permissions can access or edit it. Administrators usually have access, unless otherwise specified.
It is important to know that the registry is an important part of the operating system, and should never be tampered with unless you know what you are doing. There is a windows program that will allow you to edit the registry, called regedit.exe

There are also files that are text-based-human-readable files and they store parts of the registry. The extension for these files is .reg. These files can also be used to add or remove registry keys and values by double clicking on them, once again you should only use them when you know what you are doing or following instructions of a knowledgeable person.
I hope this helped to expand your knowledge of the Windows operating system.