Microsoft KB Archive/168748

= Java Applets Cause IE 3.02 to Stop Responding w/ SP3 =

Article ID: 168748

Article Last Modified on 11/1/2006

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APPLIES TO


 * Microsoft Windows NT Server 4.0, Terminal Server Edition
 * Microsoft Internet Explorer 3.02
 * Microsoft Windows NT Workstation 4.0 Developer Edition
 * Microsoft Windows NT Server 4.0 Standard Edition

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This article was previously published under Q168748





SYMPTOMS
Internet Explorer version 3.02 may hang when connecting to a Web link that contains a Java application after you have installed Windows NT version 4.0 Service Pack 3. The application will stop responding only if the Display Properties Color Palette is set to True Color.



CAUSE
In Windows NT version 4.0 Service Pack 3 the GetDIBits API does not fill the bit fields when a BI_RGB (uncompressed) DIB is returned on a True Color (32 bpp) display. This GDI change was made because the bit fields are not required in this case. As a side effect, this change may cause a regression in applications that expect a valid RGB mask on a True Color display.

The Java virtual machine included with Internet Explorer 3.02 calls GetDIBits when initializing the display palette. The Java virtual machine expects a valid, signed RGB mask value larger than 0x80h and, if a value less than 0x80h is received, it doubles the mask value in a tight loop until it is larger than 0x80h. Because Service Pack 3 GetDIBits do not fill the bit fields when a BI_RGB is returned, applications that evaluate the RGB mask receive an unlikely result that can be negative (for example, 0xffffffe0h.) When the Java virtual machine evaluates the RGB mask and receives a negative value, it loops forever and causes Internet Explorer to stop responding.

It is important to note that the Java virtual machine should be treating the RGB Mask as an unsigned integer. There are some conditions where an ATI video card returns a valid RGB Mask value of 0xff000000h causing the Java virtual machine to loop forever because it is not treating the mask as an unsigned integer. A separate fix for the Java virtual machine issue with ATI video cards in True Color will be available in Internet Explorer 4.0. The Java code is licensed from Sun Microsystems, Inc.



RESOLUTION
To work around this problem, do not use the True Color palette in Display Properties.

To resolve this problem, obtain the latest service pack for Windows NT 4.0 or Windows NT Server 4.0, Terminal Server Edition. For additional information, click the following article number to view the article in the Microsoft Knowledge Base:

152734 How to Obtain the Latest Windows NT 4.0 Service Pack

Win32k.sys was modified to return a valid RGB color mask on True Color display systems.

Java-fix has been superseded by Getadmin-fix. For your convenience, the English version of this post-SP3 hotfix has been posted to the following Internet location. However, Microsoft recommends that you install Windows NT 4.0 Service Pack 4 to correct this problem.

ftp://ftp.microsoft.com/bussys/winnt/winnt-public/fixes/usa/NT40/hotfixes-postSP3/getadmin-fix

You can find the original hotfix at the following Microsoft ftp site:

ftp://ftp.microsoft.com/bussys/winnt/winnt-public/fixes/usa/NT40/hotfixes-postSP3/archive/java-fix

WARNING: If you install the original (archived) version of this hotfix AFTER you apply the later version, your system may become unusable. Microsoft does not recommend you install the original hotfix after applying the later version.



STATUS
Microsoft has confirmed that this is a problem in Windows NT 4.0 and Windows NT Server 4.0, Terminal Server Edition. This problem was first corrected in Windows NT 4.0 Service Pack 4.0 and Windows NT Server 4.0, Terminal Server Edition Service Pack 4.

Additional query words: 4.00 ie 3.02 prodnt

Keywords: kbbug kbfix KB168748

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