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Improving Performance of MS-DOS Database Applications
Article ID: 219022 - View products that this article applies to.
This article was previously published under Q219022
IMPORTANT: This article contains information about modifying the registry. Before you modify the registry, make sure to back it up and make sure that you understand how to restore the registry if a problem occurs. For information about how to back up, restore, and edit the registry, click the following article number to view the article in the Microsoft Knowledge Base:
(http://support.microsoft.com/kb/256986/EN-US/ )Description of the Microsoft Windows Registry
When you use older MS-DOS-based database applications with a Windows NT or Small Business Server (SBS) network, you may encounter various errors such as:
The file is in use
The file is already open
Unable to write to drive X:
The network drive X: is no longer available
These older MS-DOS-based database application engines were not developed with the file locking mechanisms that Windows NT enables by default. These settings are used to improve performance of Windows NT-aware applications, but can have different results with applications that do not understand them. The best solution is to upgrade the application to one that is compatible with Windows NT or SBS. If it is not possible to upgrade the application, there are changes in the registry that could improve the performance. These registry entries will turn off the use of opportunistic file locking and the caching of files previously open but now closed, and will prevent the networking portion from closing a workstation session that it thinks has timed out.
WARNING: If you use Registry Editor incorrectly, you may cause serious problems that may require you to reinstall your operating system. Microsoft cannot guarantee that you can solve problems that result from using Registry Editor incorrectly. Use Registry Editor at your own risk.
Perform the following steps to disable opportunistic locking and caching of open files:
For additional information about EnableOplocks, please see the following article(s) in the Microsoft Knowledge Base:
102967For additional information about CachedOpenLimit, please see the following article(s) in the Microsoft Knowledge Base:
(http://support.microsoft.com/kb/102967/EN-US/ )REG: Server Service Entries, PART 1
124916For additional information about Autodisconnect, please see the following article(s) in the Microsoft Knowledge Base:
(http://support.microsoft.com/kb/124916/EN-US/ )Some Client Applications Fail When Writing to Windows NT
(http://support.microsoft.com/kb/138365/EN-US/ )How the Autodisconnect Works in Windows NT