There are number of BOOT.INI switches
that are useful for driver developers that wish to test their drivers under a
variety of different system configurations without having to have a separate
machine for every one. For example, limiting the amount of memory NT sees can
be useful for stressing memory loads, and limiting the number of processors for
testing scalability. I've compiled a complete list of the options that BOOT.INI
currently supports. Switches new to Win2K are in red. This list is reproduced
in the Startup, Shutdown and Crashes chapter of Inside Windows 2000, 3rd Ed.,
where you'll find more information about the boot process.
/PAE This
has NTLDR load ntkrnlpa.exe, which is the version of the x86
kernel that is able to take advantage of Intel Physical Address
Extensions (PAE), even when a system doesn't have more than 4GB of physical
memory. PAE permits an x86 sytem to have up to 64GB
of physical memory, but an operating system must be specially coded to use
memory beyond 4GB (the standard x86 limit). The PAE-version of the Win2K kernel
presents 64-bit physical addresses to device drivers, so this switch is helpful
for testing device driver support for large memory systems.
/NOPAE This switch forces NTLDR to
load the non-PAE version of the Win2K kernel, even if the system is detected as
supporting x86 Physical Address Extensions (PAE) and
has more than 4GB of physical memory.
/NOLOWMEM This switch requires that the
/PAE switch be present and that the system have more than 4GB of physical
memory. If these conditions hold, then the PAE-enabled version of the Win2K
kernel, ntkrnlpa.exe, will not use the first 4GB of physical memory. Instead,
it will load all applications and device drivers, and allocate all memory
pools, from above that boundary. This switch is useful only to test device
driver compatability with large memory systems.
/NOGUIBOOT When this option is specified
the VGA video driver responsible for presenting bit mapped graphics during
Win2K's boot process is not initialized. The driver is used to display boot
progress information, as well as to print the Blue Screen crash screen, so
disabling it will disable Win2K's ability to do those things as well.
/FASTDETECT When you dual boot NT 4.0 and
Win2K the Win2K version of NTDETECT.COM is used during the boot process. In
Win2K detection of parallel and serial devices is performed by plug-and-play
device drivers, but NT 4.0 expects NTDETECT to perform the detection. Thus,
specifying FASTDETECT causes NTDETECT to skip parallel and serial device
enumeration for a boot into Win2K, whereas ommitting
the switch has NTDETECT perform enumeration for a boot into NT 4.0. For Win2K
boots the switch is present and for boots into NT 4 the switch is omitted.
/BOOTLOG Specifying this
switch will result in NT writing a log of the boot to the file %SystemRoot%\NTBTLOG.TXT. The log has entries that detail
which drivers load and do not load during the boot process. Here is example
output from a log (note that the log file is un UNICODE):
Microsoft (R) Windows NT (R) Version 5.0
Loaded driver \WINNT\System32\ntoskrnl.exe
Loaded driver \WINNT\System32\hal.dll
Loaded driver \WINNT\System32\BOOTVID.dll
Loaded driver pci.sys
Loaded driver isapnp.sys
Loaded driver intelide.sys
...
/SAFEBOOT: You should never
have to specify this option manually, since NTLDR does it for you when you use
the F8 menu to perform a safe boot. Following the colon in the option you must
specify one of three additional switches: MINIMAL, NETWORK, or DSREPAIR. The
MINIMAL and NETWORK flags correspond to safe boot with no network and safe boot
with network support. A safe boot is a boot where NT only loads drivers and
services that are specified by name or group in the Minimal or Network Registry
keys under HKLM\System\CurrentControlSet\Control\SafeBoot.
The DSREPAIR (Directory Services Repair) switch causes NT to boot into a mode
where it restores the Active Directory from a backup medium you present.
An additional option that
you can append is "(ALTERNATESHELL)". This tells NT to use the
program specified by HKLM\System\CurrentControlSet\SafeBoot\AlternateShell
as the graphical shell, rather than to use the default which is Explorer.
/PERFMEM=
/PERFPAGES= These flags are not likely to be supported in the final
release of Windows 2K, as they are used to have NT reserve physical memory for
the purposes of Basic Block Testing (BBT). There is only one reference I've
been able to find BBT: the transcript
(posted at Microsoft's web site) of the
PERFMEM specifies the physical memory to reserve in MB, and PERFPAGES in number
of pages - they should not be specified together. A pointer to the reserved BBT
buffer is inserted in the Thread Environment Block (TEB) of every thread, but
there appears to be no other references to the buffer in Beta 3.
/INTAFFINITY This new switch directs the multiprocessor HAL (HALMPS.DLL)
to set interrupt affinities such that only the highest numbered processor in an
SMP will receive interrupts. Without the switch the HAL defaults to its normal
behavior of letting all processors receive interrupts.
/MAXPROCSPERCLUSTER= It seems that the multiprocessor HAL in Win2K (HALMPS.DLL)
has the ability to work with multiprocessors that are made up of
tightly-coupled clusters of smaller multiprocessors. For example, if you had an
8-way system that was made up of 2 4-way clusters, the processor IDs of each
processor would have to be specified in a cluster-oriented manner by the HAL.
The maximum cluster size is 4 and the default is 0 (system is not based on
clusters). Example: /MAXPROCSPERCLUSTER=3.
/TIMERES= On the multiprocessor HAL (HALMPS.DLL) this option will set
the resolution of the system timer. The argument is a number interpreted in
100's of nanoseconds, but the rate will be set to the closest resolution the
HAL supports that is not larger than the one
requested. The HAL supports the following resolutions:
100's of nanoseconds milliseconds
9766 .98
19532 2.0
39063 3.9
78125 7.8
The default resolution is 7.8ms. The system timer resolution affects the
resolution of waitable timers. Example: /TIMERES=9000
would set the timer to a resolution of .98ms.
/YEAR= This
option is obviously present for Y2K testing. Specifying it causes NT core time
function to ignore the year that the computer's
real-time clock reports and instead use the one indicated. Thus, the year used
in the switch affects every piece of software on the system, including the NT
kernel. Example: /YEAR=2001. Note: this option is only available on NT 4.0,
Service Pack 4 and later, and Windows 2000.
/USE8254 This
switch is intended for systems with older BIOS's. It instructs the NT HAL to
use the 8254 timer chip as its base timer. See Microsoft
KB Article Q169901 for more information.
/MAXMEM= This option
will limit NT to using only the amount of memory you specify. The number is
interpreted as MB. Example: /MAXMEM=16 would limit NT to using 16MB of the
system's memory.
/BURNMEMORY= This option will cause
NT to "forget" about the amount of memory specified, which limits
memory like /MAXMEM. The value specified is interpreted as MB. Example:
/BURNMEMORY=128 would have NT discard 128MB of the physical memory on the
machine as unusable.
/ONECPU This
option will have NT only enable one CPU of a multiprocessor system.
/NUMPROC= Only the
number of CPUs specified will be enabled. Example: /NUMPROC=2 on a 4-way system
will cause 2 of the 4 processors to be unused by NT.
/SOS Causes
NT to print information about what drivers are being loaded as the system
boots.
/BASEVIDEO Causes NT to
use the standard VGA display driver when moving to GUI mode.
/NODEBUG Prevents
kernel-mode debugging from being initialized. Overrides the specification of
any of the three debug-related switches, /DEBUG, /DEBUGPORT and /BAUDRATE.
/CRASHDEBUG If you include this
switch, the kernel debugger is loaded when the system boots, but remains
inactive unless a crash occurs. This allows the COM port that you specify (or
COM1 by default) to be available for other use while the system is running.
/DEBUG Enables
kernel-mode debugging.
/DEBUGPORT= Enables
kernel-mode debugging and specifies an override for the default serial port
(COM1) to which a remote debugee is connected.
Example: /DEBUGPORT=COM2.
/BAUDRATE= Enables
kernel-mode debugging and specifies an override for the default baud rate
(19200) at which a remote debugee will connect.
Example: /BAUDRATE=115200.
/BREAK Causes
the HAL to stop at a breakpoint at HAL initialization. The first thing that the
NT kernel does when it initializes is to initialize the HAL, so this breakpoint
is the earliest one possible. The HAL will wait indefinitely at the breakpoint
until a debugger connection is made. If the switch is used without the /DEBUG
switch the system will Blue Screen with STOP code of 0x00000078
(PHASE0_EXCEPTION).
/KERNEL=
/HAL= These options specify overrides of NTLDR's selection of the file named NTOSKRNL.EXE in the
system root (<winnt>\system32) as the kernel's
image file and of the file named HAL.DLL as the HAL image file. They are
extremely useful for alternating between a checked kernel environment and a
free kernel environment. If you wish to boot into a checked environment that
consists solely of the checked kernel and HAL, which is typically all that is
needed to test drivers, follow these steps on a system installed with the free
build (retail NT):
1. Copy the checked version of the kernel from the checked
build distribution CD to your <winnt>\system32
directory, naming it NTOSKCHK.EXE. If you are on a uniprocessor
then copy NTOSKRNL.EXE, otherwise on a multiprocessor copy NTKRNLMP.EXE. Note
that the kernel file name must be a 8.3-style short
names.
2. Copy the checked version of the HAL from the checked build
distribution CD to your <winnt>\system32
directory, naming it HALCHK.DLL. To determine which HAL to copy, go into your
<winnt>\repair directory and open setup.log in Notepad. Search for HAL.DLL and you'll find a
line like
"\WINNTF\system32\hal.dll="halmps.dll","1a01c". The
name to the right of the equal sign is the name of the HAL you should copy.
Note that the kernel file name must be a 8.3-style
short names.
3. Make a copy of the default line in the system's BOOT.INI.
4. In the string description of the boot selection add
something that indicates that the new selection will be for a checked build
environment e.g. "Windows NT Server Version 4.0 CHECKED".
5. Add the following to the end of the new selection's line:
/KERNEL=NTOSKCHK.EXE /HAL=HALCHK.DLL
You're done. Now you can select the
new line to boot into a checked environment or select the pre-existing
selection to boot into the free build.
/3GB This
switch made its debut in NT 4.0 Service Pack 3 and is supported on all later
releases of NT. It will cause the split between the user and system portions of
NT's virtual address map to move from 2GB user, 2GB system to 3GB user, 1GB
system. Giving virtual memory intensive applications like database servers a
larger address space can improve their performance. Note, however that for an
application to take advantage of this feature two additional conditions must
hold: The system must be part of the NT Enterprise suite (SP3 is not) and the
application must be flagged as a 3GB-aware application. See Microsoft
KB Article Q171793 for additional information.
/WIN95 This
switch is only pertinent on a triple-boot system that has DOS, Win9x and
Windows NT installed. Specifying the /WIN95 switch directs NTLDR to boot the
Win9x boot sector stored in BOOTSECT.W40. See Microsoft
KB Article Q157992 for more information.
/WIN95DOS This switch
is only pertinent on a triple-boot system that has DOS, Win9x and Windows NT
installed. Specifying the /WIN95DOS switch directs NTLDR to boot the DOS boot
sector stored in BOOTSECT.DOS. See Microsoft
KB Article Q157992 for more information.
/PCILOCK Stops
Windows NT from dynamically assigning IO/IRQ resources to PCI devices and
leaves the devices configured by the BIOS. See Microsoft
KB Article Q148501 for more information.
/NOSERIALMICE=[COMx | COMx,y,z...] Disables
serial mouse detection of the specified COM port(s). Use this switch if you
have a component other than a mouse attached to a serial port during the
startup sequence. If you use /NOSERIALMICE without specifying a COM port,
serial mouse detection is disabled on all COM ports. See Microsoft
KB Article Q131976 for more information.
/SCSIORDINAL: Adding a new SCSI
device to a system with an on-board SCSI controller can cause the controller's
SCSI ID to change, so you use this switch to direct NT to the SCSI ID of the
controller. See Microsoft
KB Article Q103625 for more information.
/noexecute=OptIn
is a setting for computers with processors without hardware
enforced DEP support which will enable software enforced DEP.
There are a couple of settings:
/NoExecute=OptIn (enables DEP for Windows system files)
/NoExecute=OptOut (enables systemwide DEP)
/NoExecute=AlwaysOn (enables systemwide DEP without pssibility of individual
application exclusion)
/NoExecute=AlwaysOff (disables DEP completely)