Desktop Heap on Windows

The system may run out of desktop heap and can be overloaded if too many jobs are running at same time under same submission account.

Refer to the following page for more information: http://support.microsoft.com/kb/184802/en

Every desktop object on the system has a desktop heap associated with it. The desktop object uses the heap to store menus, hooks, strings, and windows. The system allocates desktop heap from a system-wide 48-MB buffer. In addition to desktop heaps, printers, and font drivers also use this buffer.

Desktops are associated with Windows stations. A Windows station can contain zero or more desktops. The size of the desktop heap allocated for a desktop associated with a Windows station can be changed in the following registry value:

HKEY_LOCAL_MACHINE\System\CurrentControlSet\Control\SessionManager\SubSystems\Windows

The default data for this registry value will resemble the following (all on one line):

%SystemRoot%\system32\csrss.exe ObjectDirectory=\Windows SharedSection=1024,3072,512 Windows=On SubSystemType=Windows ServerDll=basesrv,1 ServerDll=winsrv:UserServerDllInitialization,3 ServerDll=winsrv:ConServerDllInitialization,2 ProfileControl=Off MaxRequestThreads=16

The 3 numerical values following "SharedSection=" control how desktop heap is allocated and are specified in kilobytes. There are separate settings for desktops associated with interactive and non-interactive Windows stations. Only the third value needs to be modified when system configuration is required for Dollar Universe. See section “Processes” for more details.

Every service process executed under a user account will receive a new desktop in a non-interactive Windows station created by the Service Control Manager (SCM). Thus, each service executed under a user account will consume the number of kilobytes of desktop heap specified in the SharedSection value.

The SCM creates a new desktop in the non-interactive Windows station for every service process that is running under a user account. Therefore, a larger desktop value for the SharedSection value will reduce the number of user account services that can run successfully on the system.