Introduction to Microsoft Windows NT

Windows NT (for "New Technology") is a 32-bit operating system developed by Microsoft.

Windows NT's outward appearance makes it look a lot like Windows 95/98/Millennium, but Windows NT has a separately developed kernel. Because of this, Windows NT has the following characteristics:

• Windows NT is a preemptive multitasking system;
• Windows NT is a multi-user system, which means that depending on the user who is connected to the system, the interface might be different, as might system privileges;
• Windows NT natively supports numerous network features;
• Windows NT has more security, in particular for the file system (NTFS) as well as for the robustness of the OS.

NT, 2000, XP

Windows NT and security

Since Windows NT manages users, the network administrator (who holds all special privileges on the system) is able to control privileges for each user connected to the system. What's more, with the NTFS file system, which includes the capability to assign ownership for a file, each user or usergroup can be assigned specific access privileges for different system files.

Opening a session on a computer or domain

To access a system running Windows NT, it is necessary to log in with a user name and password (this is called "opening a session"). To open a session on a computer running Windows NT, a user must enter the key sequence CTRL+ALT+DEL The Session information dialog box is used to open a session on a computer or a domain.

Several options are then offered:

• User: enter the user ID (must be found in the SAM of the PDC for the session to open)
• Password: added security. Note: The password is case-sensitive.
• Domain: for opening a session on a domain. It is possible to open a session on a computer or to open a session locally. In the latter case, the local SAM is checked.
• Open a session with the RAS: Selecting this option allows a user to open a session remotely, if the RAS service is installed.
• Shut Down: Closes all files, saves system data, and prepares the computer to be safely switched off. In NT Server, this button is disabled in order to prevent a non-authorised user from shutting down the system.

The Windows NT Security dialog box

When a user opens a session, the sequence CTRL+ALT+DEL opens another dialog box called Windows NT Security. These are the options it offers:

• Lock workstation: Ensures the computer's security without closing the session. All applications will continue running. A system can only be unlocked by the current user or by an administrator.
• Change password: Lets a user change his or her password The user must know the current password to be able to change it.
• Close session: Closes the current session, but NT's services will stay active. For security reasons, you should always close a session when you no longer need to use the computer.
• Task manager: Shows which applications are running. This option also lets you switch between applications and end an application that has stopped responding.
• Shut Down: Closes all files, saves system data, and prepares the server to be safely switched off.
• Cancel: Closes the dialogue box.