Another cool new feature in Windows Server 2008 is called “parallel session creation”. Mark Russinovich explained a little about parallel session creation at WinHEC 2007. Mark explained, “Prior to Server 2008, session creation was a serial operation. If you’ve got a Terminal Server system, or you’ve got a home system where you’re logging into more than one user at the same time, those are sessions. And the serialization of the session initialization caused a bottleneck on large Terminal Services systems. So Monday morning, everybody gets to work, they all log onto their Terminal Services system like a few hundred people supported by the system, and they’ve all got to wait in line to have their session initialized, because of the way session initialization was architected.”

Prior to Vista and Windows Server 2008, session creation was done serially by the Session Manager (SMSS) which would result in a bottleneck for Terminal Services. The SMSS created the Winlogon and Csrss processes for each session. Winlogon (which is the interactive logon manager) would then create the Local Security Authority(Lsass.exe) and Services (services.exe) processes.

In Vista and Windows Server 2008, this behavior follows a similar model to the Windows Installer service. The Initial SMSS creates an instance of itself to initialize each session. This permits parallel session creation of anywhere between 4 and the number of processors.

The initial SMSS process runs in Session 0 and runs Wininit.exe. Wininit starts what Winlogon used to start, namely lsass.exe and services.exe. It also starts a new process, the Local Session Manager (lsm.exe).

Once each subsequent session is started, that sessions SMSS create the session specific instances of winlogon and csrss.

This process will allow more concurrent users to log on to a terminal services server at the same time with much less stress on the operating system and provide faster logon times for the users.

Since the initial SMSS process runs in Session 0, the Console user now runs in Session 1 and cannot connect to Session 0. This eliminates name collisions and prevents poorly written services from displaying windows to the user. Prior to Vista, the console user ran in Session 0, which allowed the opportunity for “shatter” attacks.

Technorati : Logon Time, Session Creation, Terminal Services, Windows Server 2008
Del.icio.us : Logon Time, Session Creation, Terminal Services, Windows Server 2008
Ice Rocket : Logon Time, Session Creation, Terminal Services, Windows Server 2008