RezBook on a Network

Important information for users running RezBook across a network.

Situation:
You share your RezBook database(s) over a network and want to avoid database corruption.
There is a known issue on a Windows 2000/ XP workstation computer that can affect any application attempting to access shared database files across a network. The issue is a result of a default setting configured in the Windows 2000/XP operating system known as “Opportunistic Locking”. When a RezBook workstation attempts to access shared database files located on another Windows 2000/XP computer, the Windows 2000/XP operating system will attempt to increase performance by locking the files and caching information locally.
In addition, according to Microsoft, opportunistic locking can increase the risk of database corruption when a file is shared by two or more clients on a network file server.


Summary Information about Opportunistic Locking on Windows NT/2000/XP

1. Opportunistic locking, if enabled, can corrupt ANY database shared over a network from a server running Windows NT, 2000, or XP. This includes Microsoft Access, Borland Paradox, Omnis, Lotus Domino and many others.
2. Opportunistic locking is enabled, by default, when Windows NT, 2000, or XP is installed.
3. Opportunistic locking is re-enabled whenever a Service Pack is applied to Windows NT, 2000, or XP.

For more detailed information regarding Opportunistic Locking, please see the following Microsoft Knowledgebase articles:
Opportunistic Locking on Windows 2000/XP – http://support.microsoft.com/support/kb/articles/q296/2/64.asp

STATUS

Extract from http://support.microsoft.com/?kbid=812599

Windows XP

Microsoft has confirmed that this is a problem in the Microsoft products that are listed at the beginning of this article. This problem was first corrected in Microsoft Windows XP Service Pack 2.

Windows 2000

Microsoft has confirmed that this is a problem in the Microsoft products that are listed at the beginning of this article. This problem was first corrected in Microsoft Windows 2000 Service Pack 4.


Workaround if service pack not available:

Disable Opportunistic Locking on the Workstation or Server computers to avoid “Access Denied” error messages and possible corruption in the RezBook database files.

Disabling Opportunistic Locking on Windows 2000/XP:

Opportunistic locking can be disabled either by downloading and installing the REG utilities listed below, or manually entering the below registry entries into the workstation or server computers.


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:
256986 Description of the Microsoft Windows Registry


Disclaimer: Rubber Tree makes no warranties for the instructions given in the Microsoft Knowledgebase article referenced above, or for the utilities and registry entries reproduced on this web page. You agree to make all registry changes at your own risk.


To disable Opportunistic Locking by downloading and installing the Windows 2000/XP registry utility:
1. Click on the desired REG file listed below to begin downloading the file:
Workstation Registry Utility
Oplocks.reg
Server Registry Utility
Oplocks server.reg2. Store the file to a temporary folder on the desired workstation or server computer.
3. Once downloaded, double-click on the file to add the entry to the Windows registry.
4. Re-boot the computer.
5. Perform the above steps on all Windows 2000/XP computers.

To disable Opportunistic Locking manually on a Windows 2000/XP Workstation computer:
1. Enter the OplocksDisabled entry into the below registry key:
HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\MRXSmb\Parameters\
OplocksDisabled REG_DWORD 0 or 1
Default: 0 (not disabled)
2. Set the value to 1 to disable Oplocks
3. Reboot the workstation computer.
NOTE: The OplocksDisabled registry value configures Windows clients to either request or not request opportunistic locks on a remote file.

To disable Opportunistic Locking manually on a Windows 2000/XP Server computer:
1. Enter the EnableOplocks entry into the below registry key:
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\LanmanServer\Parameters
EnableOplocks REG_DWORD 0 or 1
Default: 1 (Enabled by Default)
2. Set the value to 0 to disable Oplocks.
3. Reboot the server computer.
NOTE: The EnableOplocks value configures Windows-based servers (including Workstations sharing files) to allow or deny opportunistic locks on local files.

Other Important Notes
” By “server” we are referring to the computer that will be hosting the RezBook database(s). By “workstation” we are referring to any of the computers that are accessing the RezBook database(s) that reside on the server.
” If Windows 98 is being used on any of the RezBook servers or workstations you must determine the manufacturer of the installed network card. If any of the computers have Realtek network cards, you must be sure the network card drivers have been updated. If the computers have the original drivers provided by Microsoft for Realtek network cards then the computers will cause corruption in the RezBook database. Please see the Realtek Network Cards and Windows 98 section of this document for information about determining the manufacturer of the installed network card and updating the driver, if necessary.
” If any of the RezBook servers or workstations are running Windows 98, or ME you should check the CONFIG.SYS file to be sure that some variables are set correctly. Please see the Windows 98, and ME Configuration File section of this document for information on how to check the CONFIG.SYS file and set the necessary variables correctly, if necessary.


Realtek Network Cards and Windows 98
” When Microsoft released Windows 98 they did not include the correct drivers for Realtek network cards.
” Using Microsoft’s drivers for Realtek network cards can cause corruption in files accessed over the network, including REZBOOK databases.
” You should check the manufacturer of the network card installed in every computer running Windows 98. Please see the Checking Network Card Manufacturer section of this document for instructions on how to find out the manufacturer of the installed network card.
” If you have determined the installed network card is made by Realtek you need to download an updated driver from Realtek. Please see the Downloading Updated Driver section of this document for information on how to download and install the updated driver.
Checking Network Card Manufacturer
Use the following procedure to determine the manufacturer and model of the installed network card:
a. From the Windows Start menu, choose Settings and select Control Panel.
b. Double-click on the System icon.
c. Under the Device Manager tab, click on the plus sign to the left of Network Adapters to expand the list. Windows will list all installed network adapters.
d. If you see a Realtek adapter listed you need to download and install an updated driver from Realtek. Note the model of the Realtek adapter and see the next section titled Downloading Updated Driver for instructions on how to download an updated driver.
Downloading Updated Driver
Use the following procedure to find an updated Realtek driver to download:
a. Go to the following Web site: http://www.realtek.com.tw
b. Click the Downloads button, then point to Communication Network ICs.
c. Click on the appropriate drop-down and select the model of your Realtek adapter, then click Go.
d. A list of available drivers will come up. Download the appropriate driver and save the file to the Desktop.
e. When the download is complete, open the file you downloaded. A folder will be created on the Desktop with the install files for the driver. There will also be a document included with installation instructions included in the folder. If you need any additional help updating the Realtek driver please contact Realtek support.

Windows ME, and 98 Configuration File
We highly recommend checking the CONFIG.SYS file on computers running Windows 98, and ME to be sure be sure certain settings are set correctly. Please use the following procedure to examine variables in the CONFIG.SYS file and correct them, if necessary.
1. Click the Windows Start button, then click Run. The Run dialog appears.
2. In the Open field type sysedit, then click OK.
3. Click the CONFIG.SYS window to bring it to the front.
a. If any lines begin with SWITCHES= type REM at the beginning of that line. The line should then begin with REM SWITCHES=.
b. If any lines begin with FCBS= type REM at the beginning of that line. The line should then begin with REM FCBS=.
c. If any lines begin with SETVER= type REM at the beginning of that line. The line should begin with REM SETVER=.
d. If any lines begin with FILES= change the line to FILES=200 unless the line already has FILES=200.
4. Click the File menu, then click Save.
5. Click the File menu, then click Exit.
6. Reboot the computer for the changes to take effect.

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