Windows Tips

See also: Introduction Troubleshooting flow chart + worksheet How to troubleshoot damaged data Database myths Causes of data damage How to repair How to export/import Troubleshooting FAQs Tips for preventing damaged data Inside the database Database size Windows tips

While the Clients & Profits relational database is generally stable and reliable, it does has an essential weak point in high-volume environments. For example, there is no server-side error-checking of the data, unlike Oracle and SQL Server-based databases (such as the one used in Clients & Profits SQL). This means Clients & Profits relies on the user’s PC to write data to the file server. Any problems on the client side, the network, or with the file server could cause lost or incomplete data, possibly corrupting the database. The impression that the network is OK is not always correct, especially in high-traffic situations. In these cases, many times corrupted packets can slip through. More often than not, the cause of the corrupted datafile is some network issue. There are several steps a system manager can take to better “bulletproof” their systems. Consider the following tips if you're regularly experiencing problems like these: Frequently occurring"update or delete command without a read/write file" error messages Frequent padlocks when starting or quitting Clients & Profits Changes are frequently not saved when editing jobs, estimates, traffic, and schedules The database becomes damaged often (i.e., weekly), especially when many users are working together The users' PCs frequently freeze or crash when saving Use caution with "optimization" utilities: Several popular system optimization programs (e.g., First Aid, etc.) suggest to the user that disabling "write-back caching" is bad, and will often re-enable it. Since few computer technicians (and even fewer users) are familiar with multi-user relational databases like Clients & Profits, be sure that they're aware that write-back caching can be harmful. To enable the VERIFY disk option in Windows 95/98 The VERIFY control turns on the operating system's built-in disk error detection and automatic correction. If VERIFY is off, your system cannot detect disk "write" (i.e., saving) errors and will make no attempt to correct them on-the-spot. If VERIFY is on, your system will automatically check for errors every time it "writes" to the hard disk to ensure it was accurate. VERIFY is disabled as a default setting because it slows down Windows (which makes sense, since most PC users aren't using multi-user relational databases over networks). VERIFY is enabled by modifying the PC's AUTOEXEC.BAT file: 1 Open your C: drive, then find and select the AUTOEXEC.BAT file. 2 Click the right mouse button, then choose Edit from the pop-up menu. The AUTOEXEC file should be opened by the Notepad, a text editor in which you can make changes. Be very careful not to change any existing autoexec commands (if so, your system may not run). 3 Add this line to the end of the AUTOEXEC file: VERIFY = ON This command should be located before any command which may cause information to be written to disk. It can be first line of the AUTOEXEC file. 4 Choose File > Save to save your changes. 5 Choose Start > Shut Down to restart your PC. The change you made to AUTOEXEC file to enable disk verification won't take affect until the computer is restarted. 6 Click the Close button then restart your PC. Be sure to repeat these steps for every Windows-based PC that uses Clients & Profits, including the file server. To disable the "write-behind caching" in Windows 95/98 Write-behind caching is a technique employed by Windows to improve a PC's performance. Write-behind caching attempts to optimize how the hard drive saves data from the computer's memory. This type of caching stores information that needs to be written to the hard disk and sends it when the system is idle or after a certain amount of time has elapsed. This is a built-in feature of Windows 95/98 and makes the PC slightly faster by essentially not double-checking that the data from memory was saved entirely to the drive. Single-user, document-based applications, such as Microsoft Word, Excel, and PowerPoint, are saved in such a way that the write-behind cache isn't needed. Database applications (especially multi-user programs like Clients & Profits) expect that the data in memory is saved completely to the hard disk. When the write-behind caching is enabled, it's possible for user's data to be saved incompletely (or not at all). By disabling the write-behind cache, the PC saves data slightly slower -- but much more reliably. In cases where unexplained data problems are occurring regularly, the write-behind caching should be disabled. 1 Select the My Computer icon, then press the right button on your mouse and choose Properties from the pop-up menu. 2 From the System Properties window click on the Performance tab. 3 Click on the File System button. 4 When the File System Properties window opens, click on the Troubleshooting tab. 5 Select "disable write-behind caching for all drives" then click OK. 6 Click the Close button, then restart your PC. Be sure to repeat these steps for every Windows-based PC that uses Clients & Profits, including your file server. Windows for Workgroups 3.11 users: Write-behind caching is provided by the SmartDrv utility in Windows 3.11. Special instructions for disabling caching on this OS is available by calling (800) 521-2166. To disable “opportunistic locking” on the Windows NT server Opportunistic locking is a technique used by Windows NT to increase the file server’s performance by performing read-ahead, write-behind, and record lock caching. Opportunistic locking is a feature on Windows NT 3.51, 4.0, and later versions. These instructions work with Windows NT 4.0. It works like this: if one client is accessing a block range in a file, that range is marked for opportunistic locking and the client can perform read-ahead, write-behind, and lock caching. If another user attempts to write to that block range, the opportunistic locking has to be switched off for the previous client and the data needs to be synchronized with the file server before the second user can access the range. The architectural of multi-user relational databases conflict with opportunistic locking, since database involve nearly constant reading, writing, and locking of the data file. Disabling opportunistic locking will improve the performance and reliability of the C&P database, but makes the server slightly less responsive for non-Clients & Profits users. For more information on opportunistic locking in Windows NT, please refer to these URLs: http://msdn.microsoft.com/library/periodic/period99/html/ewn9951.htm WARNING: Opportunistic locking is disable by editing the server’s registry information. Incorrectly editing the Windows NT registry can cause server problems, including a loss of service. It should be performed only by an experienced Windows NT technician. 1 Choose Start > Run, enter the word regedit then click OK. 2 Click on the symbol next to HKEY_LOCAL_MACHINE to expand the local computer’s settings. 3 Click on the symbol next to SYSTEM to expand the system settings. 4 Click on the symbol next to CurrentControlSet. 5 Click on the symbol next to Services. 6 Click on the heading Parameters. 7 Choose Edit > New > DWORD value. 8 Enter the Name field as EnableOplocks. 9 Choose Registry > Exit to quit the Windows Registry. 10 Restart the Windows NT server. The changes you made take affect immediately once the server has restarted. To set the “balanced” setting on the Windows NT server The Windows NT server is optimized by default to maximize sharing files. This setting makes copying documents to and from the server faster, but isn’t an efficient setting for relational databases like Clients & Profits. A simple change to the server’s network configuration will improve the performance of Clients & Profits, especially on servers with lots of users. The server must be restarted after changing this setting. Before making this change, be sure that no one is currently connected to the server. 1 Choose Start > Settings > Control Panels 2 Double-click on the Network control panel. 3 Click on the Services tab. 4 Double-click on Server from the Services list. 5 Select the Balanced setting then click OK. 6 Click Close then restart Windows NT .