System is a predefined final class, out is a PrintStream object and println is a built-in overloaded method in the out object.

The system checks the SYSTEM.DAT file for the first part of the Registry file and processes it. SYSTEM.DAT is a hidden file that contains all the system's hardware configuration information, including the PnP and application settings. It is always located under the \Windows folder. Windows 9x searches the Hkey_Local_Machine key and the user's home directory for user profile information. Windows 9x creates a folder for each user who logs on to the system. This profile is held in the \Windows\Profiles subdirectory. Each profile contains a USER.DAT file (the second half of the Registry) that holds the Registry information for that user. It also contains a number of other files that customize the desktop just for that user. As with the SYSTEM.DAT file, the USER.DAT file is backed up as USER.DA0 each time the Windows 95 system is rebooted. Under Windows 98, the USER.DAT backup is part of the rb000x.cab files.

The Clone() method returns a new array (a shallow copy) object containing all the elements in the original array.  The CopyTo() method copies the elements into another existing array.  Both perform a shallow copy.  A shallow copy means the contents (each array element) contains references to the same object as the elements in the original array.  A deep copy (which neither of these methods performs) would create a new instance of each element's object, resulting in a different, yet identacle object.

IO.SYS loads the WIN.COM file into RAM, which controls the loading and testing of the Windows 9x core components.

The contents of the Windows 9x Registry are located in two files: USER. AT and SYSTEM. AT.