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AR# 3785

V1.4 COREGEN: Blank DOS box appears when COREGen is invoked with Windows Display set to "True Color", entire program hangs; Windows NT.


Keywords: coregen, hang, display, DOS, True Color, Windows NT

Urgency: standard

General Description:
COREGen may be unable to start up on some machines if the
Windows Display setting is set to "True Color", and Resolution
is set to higher than 800x600. A blank DOS box pops up to the
foreground instead of staying resident in the Taskbar, and
the system just hangs.

The problem has been observed on a PC with a 21" Viewsonic
monitor controlled by an ATI Graphics Pro card with 4MB of video memory. The main system contained 64MB of RAM,
and was running Windows NT 4.0 Service Pack 3.



The fix is to change the colors setting for the DISPLAY
to 256 colors. After changing this setting, COREGen should
then able to proceed forward and display the GUI
window, and otherwise run normally.


The problem appears related to the following scenario
documented on the Microsoft Web site, and may be similar to a
problem with Windows NT's interaction with Internet Explorer
and other programs that use the Java routine, GetDIBits.

Microsoft's suggested fix is to wait for the next, post-
version 3 Service Pack that contains this

The location of the documentation on this problem can be found
at the Microsoft web site at

It reads as follows:

DOCUMENT:Q168748 [winnt]
TITLE :Java Applets Cause IE 3.02 to Stop Responding w/ SP3
PRODUCT :Microsoft Windows NT
KEYWORDS:kbbug4.00 kbfile kbfix4.00

The information in this article applies to:

- Microsoft Windows NT Workstation version 4.0
- Microsoft Windows NT Server version 4.0
- Microsoft Internet Explorer version 3.02


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.


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.


To work around this problem, do not use the True Color palette in Display
Properties. To resolve this problem, obtain the hotfix mentioned below or
wait for the next 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. You can find the latest
hotfix at the following Microsoft ftp site:


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


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.


Microsoft has confirmed this to be a problem in Windows NT version 4.0. A
supported fix is now available, but is not fully regression-tested and
should be applied only to systems experiencing this specific problem.
Unless you are severely impacted by this specific problem, Microsoft
recommends that you wait for the next Service Pack that contains this fix.
Contact Microsoft Product Support Services for more information.

Additional query words: 4.00 ie 3.02 prodnt

AR# 3785
Date Created 04/14/1998
Last Updated 03/12/2000
Status Archive
Type General Article