DOCUMENT:Q191890
TITLE   :How To Obtain the Checked Build of Latest WinNT 4.0 Service Pack
PRODUCT :Microsoft Windows NT
PROD/VER:4.0 SP3
OPER/SYS:WINDOWS
KEYWORD :kbfile ntdistrib kbinfo 
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The information in this article applies to:

 - Microsoft Windows NT Server version 4.0 Service Pack 3
 - Microsoft Windows NT Workstation version 4.0 Service Pack 3
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SUMMARY
=======

Checked binaries provide error checking, argument verification, and system
debugging code not present in the free binaries.

Much of the additional code in the checked binaries is in the form of
ASSERT macros that test an expression. If the expression evaluates to
FALSE, the macro generates a kernel debugger error message and breaks into
the debugger. This lets you immediately determine the cause and location of
the error.

Use the free and checked builds of Windows NT as follows:

 - Use the free build on the host machine, running WinDbg.

 - Use the free build to develop and build a driver. Performance suffers
   in the checked build due to the additional code that is executed.

 - Use the checked build on the target computer to test and debug a driver
   during the initial phases of its development.

 - Use the free build on the target computer to test and debug your driver
   during the final phases of its development. The final testing of your
   driver must be done on a free version of the driver running the free
   build of Windows NT.

The extra protection of the checked build of Windows NT carries some
penalties. Because of the additional error checking code and debugging
information, the checked binaries are larger and run slower than the free
binaries. This can conceal synchronization or other timing-related
problems, such as race conditions, that become apparent only in the free
build.

If you run the checked build of Windows NT without having enabled kernel
debugging, unexpected system shutdowns can occur. This is because the
additional checks in the checked build increase the likelihood of
encountering a breakpoint.

MORE INFORMATION
================

The checked build of Windows NT 4.0 Service Pack 3 has been posted to the
following Internet location as Sp3chki.exe (x86), Sp3csymi.exe (Symbol
files for x86), Sp3chka.exe (Alpha), and Sp3csyma.exe (Symbol files for
Alpha):

   ftp://ftp.microsoft.com/bussys/winnt/winnt-public/fixes/usa/NT40
   /ussp3/checked/

NOTE: The above link is one path; it has been wrapped for readability.

For information on how to obtain the free build of Windows NT 4.0 Service
Pack, please see the following article in the Microsoft Knowledge Base:

   ARTICLE-ID: Q152734
   TITLE     : How To Obtain the Latest Windows NT 4.0 Service Pack

Additional reference words: 4.00 sp3 servpack ntdistrib
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