Registry

Registry is a database which stores the s/w and hardware information of a computer.This resides(contains) in the file user.dat and system.dat from windows 95 version onwards ; before that there was no concept of registry apart from this all informations are stored in the following files Config.sys,autoexec.bat,system.ini,control.ini,win.ini. For editing the registry files windows supplies 'Regedit' named tool .Registry details can be exported and imported .Exported registry files with be .reg extension ;its a text based file.

REGEDIT4
[HKEY_LOCAL_MACHINE\SYSTEM\Setup]
"setup type"=dword.00000000
"cmdline"=setup_new setup
"System Perfix"=hex:c5,0b,00,00,40,36,02

In registry the hyphone symbol '-' is used for commenting.

Based upon the information registry is divided into 6 sections.

HKEY_CLASSES_ROOT
--------------------
This section contains the information of different type of file extensions,OLE related details,Drag & drop features ,Windows shortcut ,User interface etc.


HKEY_CURRENT_USER
-----------------
Contains the information of login user detials and their desktop and start menu settings.

HKEY_LOCAL_MACHINE
-------------------
This stores information about hardware and s/w details .There are many subkeys in this section

Config :
--------
Contains information about assemblence of different hardwares .

Enum :
------
It contains all details about device drivers in the PC.

Hardware :
---------
It contains information about Serial Port ,Processors,Floating Point Processers etc

Network :
--------
Network related details .

Software :
---------
Information about What all Softwares installed in the PC.

System :
--------
It deals with information about the device drivers which is uesd in the Pcand its assembly details.

HKEY_USERS
----------
Contains the information of all user detials and their desktop and start menu settings.


HKEY_CURRENT_CONFIG
-------------------
Details about Hardware Configuration.

HKEY_DYN_DATA
--------------


In registry there are 5 different datatypes

1) REG_BINARY : This datatypes are used for mainly storing hardware related informations .Its value is shhown in hexadecimal format.
2) REG_DWORD : This is 4 byte in length ,consist of boolean data 0 and 1 .Its value can be seen in hexadecimal or in decimal format .
3) REG_SZ : String datatype.
4) REG_EXPAND_SZ :
5) REG_MULTI_SZ :