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Q92766: ROM BIOS Shadowing Not an Advantage with Windows NT

Article: Q92766
Product(s): Microsoft Windows NT
Version(s): 3.1 4.0
Operating System(s): 
Keyword(s): kbenv
Last Modified: 08-AUG-2001

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The information in this article applies to:

- Microsoft Windows NT Server version 3.1 
- Microsoft Windows NT Workstation version 3.1 
- Microsoft Windows NT Server version 4.0 
- Microsoft Windows NT Workstation version 4.0 
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SUMMARY
=======

Some computers provide a ROM BIOS shadowing option. While this feature provides
an advantage with Microsoft MS-DOS, it is not an advantage with Microsoft
Windows NT.

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

ROM BIOS shadowing is the process of copying the BIOS from ROM into RAM and
using either hardware or 386 enhanced mode to remap the RAM into the normal
address space of the BIOS. Because reading RAM is much faster than reading ROM,
BIOS-intensive operations are substantially faster. For example, MS- DOS uses
the BIOS to write to the screen; therefore, with ROM BIOS shadowing, directory
listings run more quickly.

Windows NT does not use the BIOS (except during startup); therefore, no
performance is gained by shadowing. If ROM BIOS shadowing is not used, more RAM
is available. With Windows NT, there is an advantage to disabling the ROM BIOS
shadowing option.

This applies to other BIOS shadowing schemes as well. Typically the CMOS settings
allow the system to shadow any BIOS. This includes the following:

  System BIOS
  Video BIOS
  Other adapters ROM BIOS (in a given select range)

Additional query words: prodnt win32

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Keywords          : kbenv 
Technology        : kbWinNTsearch kbWinNTWsearch kbWinNTW400 kbWinNTW400search kbWinNT400search kbWinNTW310 kbWinNTSsearch kbWinNTS400search kbWinNTS400 kbWinNTS310 kbWinNTS310search kbWinNT310Search kbWinNTW310Search
Version           : 3.1 4.0

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