Available Switch Options for Windows NT Boot.ini File
Article ID: Q170756
The information in this article applies to:
Microsoft Windows NT Workstation versions 3.51 and 4.0
Microsoft Windows NT Server versions 3.51 and 4.0
SUMMARY
=======
When you start Windows NT, there are many different switches that can be
added to the Boot.ini file that will modify the way Windows NT loads. For
further boot.ini references, please see the following article in the
Microsoft Knowledge Base:
ARTICLE-ID: Q102873
TITLE : Boot.ini and ARC Path Naming Conventions and Usage
MORE INFORMATION
================
The following are the different switches that can be added to the
Boot.ini file:
/3GB
Allows user-mode applications to access 3 GB of memory instead of the
usual 2 GB that Windows NT normally allocates to user-mode applications.
It moves the starting point of kernel memory to 3 GB.
/BASEVIDEO
The /BASEVIDEO switch forces the system into standard 640x480 16-color
VGA mode. This is used to allow the system to load if the wrong video
resolution or refresh rate had been selected.
For more information, please see the following Microsoft Knowledge
Base article:
ARTICLE-ID: Q126690
TITLE : Windows NT 4.0 Setup Troubleshooting Guide
/BAUDRATE=nnnn
This switch sets baudrate of the debug port. If you do not set the baud
rate, the default baud rate is 19,200. 9,600 is the normal rate for
remote debugging over a modem. This will also enable the /DEBUG switch.
For example, /BAUDRATE=9600
For more information on modem configuration, please see the following
Microsoft Knowledge Base article:
ARTICLE-ID: Q148954
TITLE : How to Set Up a Remote Debug Session Using a Modem
For more information on null modem configuration, please see the
following Microsoft Knowledge Base article:
ARTICLE-ID: Q151981
TITLE : How to Set Up a Remote Debug Session Using a Null Modem
Cable
/CRASHDEBUG
Enables the COM port for debugging in the event that Windows NT crashes.
This allows you to use the COM port for normal operations while Windows
NT is running, but will convert the port to a debug port if Windows NT
crashes (to allow remote debugging).
For more information, please see the following Microsoft Knowledge Base
article:
ARTICLE-ID: Q151981
TITLE : How to Set Up a Remote Debug Session Using a Null Modem
Cable
/DEBUG
The /DEBUG switch enables the kernel debugger. This allows live remote
debugging of a Windows NT system through the COM ports. Unlike
/CRASHDEBUG, /DEBUG will use the COM port whether or not you are
debugging.
For more information on remote debugging, please see the following
Microsoft Knowledge Base article:
ARTICLE-ID: Q121543
TITLE : Setup for Remote Debugging
/DEBUGPORT=comx
The /DEBUGPORT=comx switch selects a COM port for the debug port
(com1, com2, com3...) DEBUGPORT defaults to COM2 if it exists,
otherwise it will use COM1. This will also enable the /DEBUG switch.
For example, /DEBUGPORT=COMx where x is the com port.
For more information, please see the following Microsoft Knowledge
Base article:
ARTICLE-ID: Q151981
TITLE : How to Set Up a Remote Debug Session Using a Null Modem
Cable
/HAL=filename
Allows you to define the actual hardware abstraction layer (HAL) to be
loaded at startup. This switch is useful in trying out a different HAL
before renaming it to hal.dll. This switch is also useful when you want
to try booting between multiprocessor and single processor mode when
used in conjunction with the /KERNEL switch. For example,
/HAL=halmps.dll. This will load Halmps.dll from the System32 directory.
/KERNEL=filename
The /KERNEL=filename switch allows you to define the actual KERNEL to
be loaded at startup. This is useful in switching between a debug
enabled kernel full of debugging code and a regular kernel. It is also
useful for forcing Windows NT to load a specific kernel. For example,
/KERNEL=ntkrnlmp.exe. This switch command will load Ntkrnlmp.exe from
the System32 directory.
/NODEBUG
This switch disables the kernel debugger. The switch turns off
debugging. This can cause a blue screen if a piece of code has a debug
hardcoded breakpoint in its software.
For more information, please see the following article in the Microsoft
Knowledge Base:
ARTICLE-ID: Q103059
TITLE : Descriptions of Bug Codes for Windows NT
/NOSERIALMICE:comx
This switch disables the mouse port check for this com port. For example,
/NOSERIALMICE:COMX, where X is the number of the serial port. Ports may
be separated with commas to disable more than one port. If no serial port
is given then ALL ports will be disabled for mouse devices.
This is used with an uninterruptible power supply (UPS) that connects to
a serial port. If this option is not available when Windows NT starts
and Windows NT tries to detect a mouse on this port, the UPS may
accidentally start its shutdown mode.
For more information, please see the following Microsoft Knowledge
Base article:
ARTICLE-ID: Q131976
TITLE : How to Disable Detection of Devices on Serial Ports
/NUMPROC=
This switch sets the number of processors that Windows NT will run at
startup. This will help test out performance problems and defective
CPUs. For example, /NUMPROC=3
/PCILOCK
This switch prevents Windows NT from enumerating the PCI bus every
time it starts up.
/SOS
The /SOS switch causes the loader to print the name of loaded modules.
When Windows NT comes up instead of displaying dots while the devices
load, Windows NT will show the actual names of the drivers as they load.
For more information, please see the following Microsoft Knowledge Base
article:
ARTICLE-ID: Q99743
TITLE : Purpose of the Boot.ini File
/ONECPU
This switch is part of Compaq's HAL. The switch tells Windows NT to use
only 1 CPU at startup. This will allow you to run a single CPU in a
multikernel configuration. For example, /ONECPU.
/WIN95
The /WIN95 switch loads bootsec.dos.
/WIN95DOS
The /WIN95DOS switch loads bootsec.w40.
For more information on /WIN95 and /WIN95DOS, please see the following
Microsoft Knowledge Base article:
ARTICLE-ID: Q157992
TITLE : How to Triple Boot to Windows NT, Windows 95, and MS-DOS