Definition of Registry Value Data Types

• Microsoft Windows NT operating system version 3.1
• Microsoft Windows NT Advanced Server version 3.1

WARNING: Using Registry Editor incorrectly can cause serious, system-wide problems that may require you to reinstall Windows NT to correct them. Microsoft cannot guarantee that any problems resulting from the use of Registry Editor can be solved. Use this tool at your own risk.

This article describes the different data types for key values in the Windows NT Registry:

• REG_BINARY
• REG_DWORD
• REG_EXPAND_SZ
• REG_MULTI_SZ
• REG_SZ

REG_BINARY

This is the raw binary data. Most hardware component information is stored as binary data, and can be displayed in Registry Editor in hexadecimal format, or displayed in WinMSD in an easy-to-read format. For example:

   Component Information : REG_BINARY : 00 00 00...

REG_DWORD

This is data represented by a number that is four bytes long. Many parameters for device driver and services are this type, and can be displayed in Registry Editor in binary, hexadecimal, or decimal format. For example, entries for service error controls are this type:

   ErrorControl : REG_DWORD : 0x1

REG_EXPAND_SZ

An expandable data string that is text containing a variable to be replaced when called by an application. For example, for the following value, the string "%SystemRoot%" will replaced by the actual location of the directory containing the Windows NT system files:

   File : REG_EXPAND_SZ : %SystemRoot%\file.exe

REG_MULTI_SZ

This is a multiple string. Values that contain lists or multiple values in human readable text are usually this type. Entries are separated by NULL characters. For example, the following value entry specifies the binding rules for a network transport:

   bindable : REG_MULTI_SZ : dlcDriver dlcDriver non non 50

REG_SZ

This is a sequence of characters representing human readable text. For example, a component’s description is usually this type:

   DisplayName : REG_SZ : Messenger