DOCUMENT:Q102611  16-AUG-1993  [W_NT]
TITLE   :INF: Windows NT VDMs Keep Their Own System Time
PRODUCT :Windows NT
PROD/VER:3.10
OPER/SYS:WINDOWS
KEYWORDS:

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The information in this article applies to:

 - Microsoft Windows NT operating system, version 3.1
 - Microsoft Windows NT Advanced Server, version 3.1
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SUMMARY
=======

Windows NT virtual DOS machines (VDMs) keep their own system time.
Each time an MS-DOS-based application or a 16-bit Windows-based
application is started, its BiosDataArea tick count is initialized to
the current system time. When an MS-DOS-based application sets the
time in a VDM, it is reflected in that VDM only. When a 16-bit
Windows-based application changes the time, the new time is reflected
in all 16-bit Windows-based applications running in Windows on Windows
(WOW).

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

Windows NT is designed this way because MS-DOS-based applications
depend on timer tic hardware for their sense of time. Many
MS-DOS-based applications do not interact favorably with the timer tic
hardware.

Additional reference words: 3.10
KBCategory:
KBSubCategory: winnt

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Copyright Microsoft Corporation 1993.