Windows® Internals, Sixth Edition, Part 2

Requires that PAE be enabled and that the system have more than 4 GB of physical memory. If these conditions are met, the PAE-enabled version of the Windows kernel, Ntkrnlpa.exe, won’t use the first 4 GB 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 compatibility with large memory systems.

numproc

Number of processors

Specifies the number of CPUs that can be used on a multiprocessor system. Example: /NUMPROC=2 on a four-way system will prevent Windows from using two of the four processors.

nx

OptIn, OptOut, AlwaysOff, AlwaysOn

This option is available only on 32-bit versions of Windows when running on processors that support no-execute memory and only when PAE (explained further in the pae entry) is also enabled. It enables no-execute protection. No-execute protection is always enabled on 64-bit versions of Windows on x64 processors. See Chapter 9 for a description of this behavior.

onecpu

Boolean

Causes Windows to use only one CPU on a multiprocessor system.

optionsedit

Boolean

Enables the options editor in the Boot Manager. With this option, Boot Manager allows the user to interactively set on-demand command-line options and switches for the current boot. This is equivalent to pressing F10.

osdevice

GUID

Specifies the device on which the operating system is installed.

pae

Default, ForceEnable, ForceDisable

Default allows the boot loader to determine whether the system supports PAE and loads the PAE kernel. ForceEnable forces this behavior, while ForceDisable forces the loader to load the non–PAE version of the Windows kernel, even if the system is detected as supporting x86 PAEs and has more than 4 GB of physical memory.

pciexpress

Default, ForceDisable

Can be used to disable support for PCI Express buses and devices.

perfmem

Size in MB

Size of the buffer to allocate for performance data logging. This option acts similarly to the removememory element, since it prevents Windows from seeing the size specified as available memory.

quietboot

Boolean

Instructs Windows not to initialize the VGA video driver responsible for presenting bitmapped graphics during the boot process. The driver is used to display boot progress information, so disabling it will disable the ability of Windows to show this information.

ramdiskimagelength

Length in bytes

Size of the ramdisk specified.

ramdiskimageoffset

Offset in bytes

If the ramdisk contains other data (such as a header) before the virtual file system, instructs the boot loader where to start reading the ramdisk file from.

ramdisksdipath

Image file name

Specifies the name of the SDI ramdisk to load.

ramdisktftpblocksize

Block size

If loading a WIM ramdisk from a network Trivial FTP (TFTP) server, specifies the block size to use.

ramdisktftpclientport

Port number

If loading a WIM ramdisk from a network TFTP server, specifies the port.

ramdisktftpwindowsize

Window size

If loading a WIM ramdisk from a network TFTP server, specifies the window size to use.

removememory

Size in bytes

Specifies an amount of memory Windows won’t use.

restrictapiccluster

Cluster number

Defines the largest APIC cluster number to be used by the system.

resumeobject

Object GUID

Describes which application to use for resuming from hibernation, typically Winresume.exe.

safeboot

Minimal, Network, DsRepair

Specifies options for a safe-mode boot. Minimal corresponds to safe mode without networking, Network to safe mode with networking, and DsRepair to safe mode with Directory Services Restore mode. (Safe mode is described later in this chapter.)

safebootalternateshell

Boolean

Tells Windows to use the program specified by the HKLM\SYSTEM\CurrentControlSet\Control\SafeBoot\AlternateShell value as the graphical shell rather than the default, which is Windows Explorer. This option is referred to as Safe Mode With Command Prompt in the alternate boot menu.

sos

Boolean

Causes Windows to list the device drivers marked to load at boot time and then to display the system version number (including the build number), amount of physical memory, and number of processors.

stampdisks

Boolean

Specifies that Winload will write an MBR disk signature to a RAW disk when booting Windows PE (Preinstallation Environment). This can be required in deployment environments in order to create a mapping from operating system–enumerated hard disks to BIOS-enumerated hard disks to know which disk should be the system disk.

systemroot

String

Specifies the path, relative to osdevice, in which the operating system is installed.

targetname

Name

For USB 2.0 debugging, assigns a name to the machine that is being debugged.

tpmbootentropy

Default, ForceDisable, ForceEnable