Wednesday, October 21, 2009

Common processes

lsass - Local Security Authentication Server

The process lsass.exe serves as the Local Security Authentication Server by Microsoft, Inc. It is responsible for the enforcement of the security policy within the operating system. This process checks whether a user’s supplied identification is valid or not whenever he or she tries to access the computer system.
With the execution of the file lsass.exe, the system acquires security by preventing the access of unwanted users to any private information. The file lsass.exe also handles the password modifications done by the user.

lsm - Local Session Manager

Local Session Manager. Process found on Windows Vista and whose role is to manage the terminal server connections to the machine. In Vista, terminal server sessions are not just Remote Desktop sessions from remote users as they are in Windows XP/2003, they are also your sessions when you are logged in to the PC at the PC itself, as all sessions, whether local or remote, are virtualised terminal server sessions. It follows, therefore, that this process is a crucial core process of Windows Vista.


is a process belonging to the Windows login manager. It handles the login and logout procedures on your system. This program is important for the stable and secure running of your computer and should not be terminated


is a part of the Microsoft Windows Operating System and manages the operation of starting and stopping services. This process also deals with the automatic starting of services during the computers boot-up and the stopping of services during shut-down. This program is important for the stable and secure running of your computer and should not be terminated.


This is a system critical process, as long as it exists in %windir%\system32. Its job is to start some of the core Windows Vista background services.

csrss - Windows Client/Server Runtime Server Subsystem

The Microsoft Client Server Runtime Server subsystem utilizes the process csrss.exe for managing the majority of the graphical instruction sets under the Microsoft Windows operating system. As such Csrss.exe provides the critical functions of the operating system, and its termination can result in the Blue Screen of Death being displayed.

Csrss.exe controls threading and Win32 console window features. Threading is where the application splits itself into multiple simultaneous running tasks. Threads supported by csrss.exe are different from processes in that threads are commonly contained within the process, with various threads sharing resources within the same process. The Win32 console is the plain text window in the Windows API system (programs can use the console without the need for image display).

In mobile devices such as notebooks and laptops, the process csrss.exe is closely dependent on power management schemes implemented by the system as defined under the Control Panel option.

smss - Session Manager Subsystem

The Session Manager Subsystem is responsible for starting a user's session. When this process begins, the system thread is responsible for a number of specific tasks including launching the Winlogon, specific Win32 processes and among other items, setting the system variables.
Many computer users first notice the SMSS.exe process when a system shuts down abnormally. For instance, when a Winlogon ends normally, this process usually has no problem fulfilling its tasks, however, when a system shuts down abnormally or unexpectedly, the SMSS.exe causes a "hang" which is when the system stops responding.

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