Microsoft KB Archive/328237

= Some programs do not work as expected when large files are opened =

Article ID: 328237

Article Last Modified on 2/19/2007

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APPLIES TO


 * Microsoft Windows XP Professional
 * Microsoft Windows 2000 Advanced Server
 * Microsoft Windows 2000 Professional Edition
 * Microsoft Windows 2000 Server

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This article was previously published under Q328237





SYMPTOMS
Certain programs such as Microsoft Excel and Microsoft Word do not work as expected when you open medium to large files. A network trace shows that the redirector issues sequential reads that are 4 kilobytes (KB) to 8 KB large. The trace shows a high number of small reads posted by program when the large files are read.



CAUSE
This problem occurs because the redirector does not use the ReadAhead feature.



Service pack information
To resolve this problem, obtain the latest service pack for Windows XP. For more information, click the following article number to view the article in the Microsoft Knowledge Base:

322389 How to obtain the latest Windows XP service pack

Hotfix information
A supported hotfix is now available from Microsoft, but it is only intended to correct the problem that is described in this article. Only apply it to systems that are experiencing this specific problem. This hotfix may receive additional testing. Therefore, if you are not severely affected by this problem, we recommend that you wait for the next Windows XP service pack that contains this hotfix.

To resolve this problem immediately, contact Microsoft Product Support Services to obtain the hotfix. For a complete list of Microsoft Product Support Services telephone numbers and information about support costs, visit the following Microsoft Web site:

http://support.microsoft.com/contactus/?ws=support

Note In special cases, charges that are ordinarily incurred for support calls may be canceled if a Microsoft Support Professional determines that a specific update will resolve your problem. The usual support costs will apply to additional support questions and issues that do not qualify for the specific update in question.

File information
The English version of this hotfix has the file attributes (or later file attributes) that are listed in the following table. The dates and times for these files are listed in Coordinated Universal Time (UTC). When you view the file information, it is converted to local time. To find the difference between UTC and local time, use the Time Zone tab in the Date and Time tool in Control Panel.    Date         Time   Version            Size    File name --  24-Jun-2003  18:11  5.1.2600.1239     401,920  Mrxsmb.sys 24-Jun-2003 18:11  5.1.2600.1239     156,160  Rdbss.sys

27-Jun-2003 01:17  5.1.2600.1239      92,160  Cscdll.dll 27-Jun-2003 01:17  5.1.2600.1239   1,120,256  Ole32.dll

Hotfix information
A supported hotfix is now available from Microsoft, but it is only intended to correct the problem that is described in this article. Only apply it to systems that are experiencing this specific problem. This hotfix may receive additional testing. Therefore, if you are not severely affected by this problem, we recommend that you wait for the next Windows 2000 service pack that contains this hotfix.

To resolve this problem immediately, contact Microsoft Product Support Services to obtain the hotfix. For a complete list of Microsoft Product Support Services telephone numbers and information about support costs, visit the following Microsoft Web site:

http://support.microsoft.com/contactus/?ws=support

Note In special cases, charges that are ordinarily incurred for support calls may be canceled if a Microsoft Support Professional determines that a specific update will resolve your problem. The usual support costs will apply to additional support questions and issues that do not qualify for the specific update in question.

File information
The English version of this hotfix has the file attributes (or later file attributes) that are listed in the following table. The dates and times for these files are listed in Coordinated Universal Time (UTC). When you view the file information, it is converted to local time. To find the difference between UTC and local time, use the Time Zone tab in the Date and Time tool in Control Panel. Date        Time   Version            Size    File name --  20-Jun-2003  18:29  5.0.2195.6760     407,792  Mrxsmb.sys 20-Jun-2003 18:29  5.0.2195.6760     169,520  Rdbss.sys

20-Jun-2003 18:50  5.0.2195.6760     944,400  Ole32.dll 20-Jun-2003 18:50  5.0.2195.6753     432,400  Rpcrt4.dll 20-Jun-2003 18:50  5.0.2195.6760     187,664  Rpcss.dll



STATUS
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the &quot;Applies to&quot; section. This problem was first corrected in Microsoft Windows XP Service Pack 2.



MORE INFORMATION
The redirector has been enhanced to enable the ReadAhead feature on sequential reads. Therefore, when a program reads 4-KB or 8-KB segments in a sequential manner, the redirector engages the cache manager and prefetches the data to cache by reading a larger set of data.

Also, the following registry entry has been introduced to control the ReadAhead size:

Value name: ReadAheadGranularity

Data type: REG_DWORD

Value data: Number of pages to read ahead. The valid range is 0 to 16. The default setting is 8 pages (32 KB).

The ReadAhead feature is disabled if hotfix 894463 is installed. Therefore, you must manually enter the ReadAheadGranularity registry entry. To do this, following these steps:
 * 1) Click Start, click Run, type regedit, and then click OK.
 * 2) Locate and then right-click the following registry subkey:


 * 1) On the Edit menu, point to New, and then click DWORD Value.
 * 2) Type ReadAheadGranularity, and then press ENTER.
 * 3) On the Edit menu, click Modify.
 * 4) Click Decimal, type 8 in the Value data box, and then click OK.

Note There are few scenarios where you may have to modify the  registry entry. For example, you may have to change this setting on a lossy WAN link or a heavily loaded Terminal server to a setting of 4 ( this setting equals a 16-KB read size). Typically, when Windows reads large files sequentially, the program performs better if the program posts larger read sizes. For more information about how to obtain a hotfix for Windows 2000 Datacenter Server, click the following article number to view the article in the Microsoft Knowledge Base:

265173 The Datacenter Program and Windows 2000 Datacenter Server Product

Additional query words: slow delay sluggish long time fileopen office excel word powerpoint

Keywords: kbhotfixserver kbwinxpsp2fix kbwinxppresp2fix kbwin2000presp5fix kbqfe kbbug kbfix KB328237

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