The HKEY_LOCAL_MACHINE key contains the settings for IRQ's, network cards, video cards and other hardware data. These settings are used by all the users of a computer system.

There are several important subkeys:

  • Config
    The Config subkey tracks hardware configurations.

  • Enum
    The Enum subkey contains information about the hardware devices and the bus enumeration. This information is used to build and store the hardware device tree.

  • Software
    The Software subkey contains the information about every registered program that is compatable with the registry. The 32-bit programs should self-register in the registry. The 16-bit programs require manual editing or specifically setting up the program to self-register. The Classes sub-subkey contains OLE and extension information. The Description sub-subkey are set up by manufacturers to describe their data and programs.

  • System
    The System subkey holds the configuration information used during the startup sequence. The Control sub-subkey contains startup and printer information. The Service sub-subkey contains the order to load device drivers.

  • Hardware
    The Hardware subkey cntains information about the CPU and the serial ports.

  • Network
    The Network subkey contains the username and the server the user is logged on to.

  • Security
    The Security subkey contains the server name and the server type.