Microsoft KB Archive/103475

= Starting Applications with /REALTIME May Hang Windows NT =

Article ID: 103475

Article Last Modified on 12/5/2003

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APPLIES TO


 * Microsoft Windows NT Advanced Server 3.1
 * Microsoft Windows NT Workstation 3.1
 * Microsoft Windows NT Workstation 3.51
 * Microsoft Windows NT Workstation 4.0 Developer Edition
 * Microsoft Windows NT Server 3.51
 * Microsoft Windows NT Server 4.0 Standard Edition

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This article was previously published under Q103475





SYMPTOMS
From a Command Prompt (CMD.EXE), if you start an application with the /REALTIME switch, Windows NT may appear to hang.



CAUSE
The /REALTIME switch starts an application at a higher priority level than normal. This gives the application more processor time to use during its execution. If you use this switch on applications that are not designed for it, Windows NT will not respond to any other commands and will appear to hang, even though Windows NT is actually still running and executing as instructed by the command line switch.



RESOLUTION
To prevent this situation from occurring, it is possible for the Administrator of the system to set a User's rights so they are unable to use this feature of setting thread priorities. Power Users are given the right to Increase Scheduling Priorities by default.

To remove the right to Increase Scheduling Priorities, use the following procedure:


 * 1) Open the User Manager in the Administrative Tools group.
 * 2) Select Policy from the menu and then select User Rights.
 * 3) Select the Show Advanced User Rights check box.
 * 4) Open the Rights box.
 * 5) Select Increase Scheduling Priority.
 * 6) Remove any desired Users or Groups from the Grant To box.

Without the Increase Scheduling Priority right, users will be unable to use the /REALTIME switch.



Steps to Reproduce Problem
 Open a Command Prompt from the Main group. Type the following command:

START /REALTIME EDIT.COM

 When Edit is opened, select the File menu.

At this point, the system will not respond to any keyboard or mouse commands.

Additional query words: prodnt hung lock freeze

Keywords: KB103475

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