From: http://blog.donews.com/digivelop/
Overview of Windows PE 2.0 for Windows Vista
Publisher: Tony Northrup
Windows PE 2.0 is the core deployment foundation of Windows Vista. It is designed to make large-scale custom deployment of the new Windows Vista operating system particularly easy. When Windows Vista starts, all Windows Vista corporate customers will have access to Windows PE 2.0. (Windows PE for Windows XP remains exclusive to customers with Microsoft's "Software Assurance" (SA) agreement.) Windows PE allows users to inject drivers, configure Windows Vista offline, provide recovery solutions, and diagnose and troubleshoot system problems.
In February 2006, a pre-release version of Windows PE 2.0 generated for Windows Vista will be available for download and testing for all corporate customers participating in the Windows Vista pre-release program.
Summary
Microsoft Windows Preinstallation Environment (Windows PE) 2.0 provides powerful preparation and installation tools for the Windows Vista operating system. With Windows PE, you can boot a subset of Windows Vista from a network or removable media, providing the network and other resources necessary for installing and troubleshooting Windows Vista. This article describes Windows PE, its features, and improvements over earlier pre-installation technologies.
Page Content
Introduction
Installing with Windows PE
Troubleshooting with Windows PE
Windows PE Technology
Comparison of Windows PE 2.0 with Early Technologies
Summary
Introduction
Microsoft Windows Pre-installation Environment (Windows PE) 2.0 is a boot tool developed by Microsoft that provides operating system functionality for installation, troubleshooting, and recovery. Windows PE is not a general-purpose operating system but is dedicated to three specific tasks:
• Installing Microsoft Windows Vista. Every time Windows Vista is installed, Windows PE runs. During the installation phase, graphical tools that collect configuration information run within Windows PE. Additionally, information technology (IT) departments can customize and extend Windows PE to meet their unique deployment needs.
• Troubleshooting. Windows PE also helps with automatic and manual troubleshooting. For example, if Windows Vista fails to start due to a corrupted system file, Windows PE can automatically start the "Windows Recovery Environment". You can also manually start Windows PE to use built-in or customized troubleshooting and diagnostic tools.
• Recovery. "Original Equipment Manufacturers" (OEMs) and "Independent Software Vendors" (ISVs) can use Windows PE to create custom, automated solutions to recover and regenerate computers running Windows Vista. For example, users can boot their computers from a Windows PE recovery CD or recovery partition to automatically reformat their hard drive and reinstall Windows Vista with original drivers, settings, and applications.
This article is intended for IT professionals and describes the installation and troubleshooting features of Windows PE but does not discuss how OEMs and ISVs use Windows PE for recovery.
Basically, creating a standardized method that administrators can use to effectively track problem areas and make repairs saves valuable time spent interpreting complex error logs. Administrators can use the information in this article as tools and checklists to reduce the time spent on resolving failed connections. It can also help administrators solve their own problems before seeking help from "Microsoft Product Support Services".
Note: Since Windows PE is specifically designed as a tool for configuring, installing, and troubleshooting Windows Vista, Windows PE cannot be purchased separately from Windows Vista.
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Installing with Windows PE
Microsoft has designed Windows PE as a pre-installation environment to replace MS-DOS. Windows PE is built on top of Windows Vista components, providing a powerful, flexible, and familiar environment. In fact, Windows PE can run many Windows Vista applications, detect and enable most modern hardware, and communicate over the "Internet Protocol" (IP) network. Windows PE typically occupies less than 100 MB of disk space and can run entirely from "Random Access Memory" (RAM), allowing you to insert a second CD containing drivers or software for use. These features enable Windows PE to run on computers with currently unformatted hard drives or no operating system installed. However, unlike Windows Vista, Windows PE is not a fully functional operating system.
Customizing Windows Vista Installation
Nonetheless, enterprises will appreciate the emergence of Windows PE because IT departments will be able to create scripts and applications to automate deployment. For example, an IT department can use the following process to configure a "Windows Deployment Services" remote deployment infrastructure, create a configuration script, and generate a custom Windows PE image to enable a highly automated deployment process:
1.
When a new computer connects to the network, the built-in "Pre-Boot Execution Environment" (PXE) client connects to the "Windows Deployment Services" server and downloads the custom Windows PE image over the network.
2.
The new computer loads Windows PE into memory and starts the configuration script. The script verifies that the computer's configuration meets the IT department's hardware requirements.
Note: "Windows Deployment Server" (Windows DS) replaces "Remote Installation Services" (RIS).
3.
If necessary, the script backs up user data to a shared folder on another computer.
4.
The script runs the Diskpart tool to partition and format the disk.
5.
The script connects to a shared folder containing "Windows Vista Installation" files and runs the "Windows Vista Installation" program to install the operating system in completely unattended mode.
Windows PE and Windows Image Format
The most powerful and flexible way to distribute Windows PE is by using the "Windows Image Format" (WIM) file. WIM is a file-based image format that Windows Vista uses for fast installation on new computers. A WIM file stores copies (called images) of one or more operating systems, such as Windows Vista or Windows PE. Maintaining an operating system using a WIM file is easy because you can add and remove drivers, update content, and Windows components offline without booting the operating system. Maintaining a Windows PE image using a WIM file is very similar to maintaining a Windows Vista image.
Similar to Windows Vista, Windows PE can be included in a WIM file. But when you store a Windows Vista image in a WIM file, the only way to boot Windows Vista is to copy the image to the computer's hard drive. However, Windows PE can boot directly from a WIM file that has not been copied to the hard drive. This feature allows you to create a WIM file and store it on a bootable media, such as a CD or USB flash drive, and then boot Windows PE directly from that media. When installing Windows Vista on a new computer, Microsoft uses this feature to load Windows PE into RAM and start Windows PE.
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Troubleshooting with Windows PE
Although the main use of Windows PE is to install Windows Vista, you can also use Windows PE for troubleshooting. Examples of troubleshooting tasks include:
• Replacing system files. You can replace corrupted files on the original installation media. For example, if a corrupted system file prevents the computer from booting, you can use Windows PE to start the computer and then replace the corrupted file in the Windows Vista media.
• Restoring data before reinstalling Windows. Windows PE provides full access to FAT and NTFS file systems. In cases where you must replace or reformat the hard drive, you can first boot the computer with Windows PE and then copy important files to another disk or shared folder. Note that files encrypted with the "Encrypting File System" (EFS) are not easily recoverable.
• Running diagnostic and configuration tools. Windows PE includes common command-line diagnostic tools. You can also run other standard and custom Windows troubleshooting tools within Windows PE. Built-in tools include:
• Diskpart. Diskpart is a text-mode command interpreter that allows you to manage disks, partitions, or volumes via the command prompt or scripts.
• Drvload. You can use the drvload command to add device drivers (such as audio, video, and motherboard chipset) to the Windows PE image. You can also use drvload to dynamically load drivers after Windows PE has started.
• Net. The Net command-line tool allows you to manage the local user database, start and stop services, and connect to shared folders.
• Netcfg. This network configuration tool configures network access. When using Windows PE as a custom deployment tool, you might use Netcfg to manually configure network settings as part of a boot script.
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Windows PE Technology
To make Windows PE as universal as possible, Microsoft has designed it to be lightweight, powerful, and flexible. The following sections describe these features in more detail, followed by a description of the limitations of Windows PE.
Lightweight
Windows PE must be as small as possible to be stored on removable media, such as CDs and USB flash drives, and must be able to start quickly and run entirely from the computer's memory. The exact size of Windows PE varies depending on how the image is customized, but when compressed in WIM format, it typically occupies less than 100 MB of space. The 64-bit version of Windows PE is larger, and customizing the Windows PE image with language packs or applications increases its size.
To help minimize memory usage, run Windows PE from a compressed image. In other words, you can compress Windows PE within a WIM file and run it from memory without decompressing it. Therefore, you benefit from compression both when storing the image on disk and after loading it into the computer's memory.
To minimize disk storage, the WIM format stores only a single instance of multiple duplicate files. So if you have a WIM file with two Windows PE images, the files shared by the two images will be stored only once.
Powerful
Although Windows PE is designed to be small, it contains a large number of core features of Windows Vista. Because Windows PE supports Win32 (just like Microsoft Windows XP and Windows Vista), most Windows applications can run in Windows PE. This means that developers in IT departments can use tools like Microsoft Visual Studio to create Win32 applications that run on Windows PE.
Windows PE also supports multithreading and multitasking, so you can run multiple tools simultaneously. This feature saves time and resources that would otherwise be needed to verify and test hardware and software images using other technologies. Windows PE can also run batch files, Microsoft Visual Basic Scripting Edition (VBScript) scripts, Windows Script Host (WSH) scripts (if the optional WSH component is installed), HTML applications (HTA), and Microsoft ActiveX Data Objects (ADO). Because Windows PE provides RAM-based temporary space, Windows PE can run applications that need to write temporary files to the hard drive (even if there is no available hard drive).
To minimize disk storage, the WIM format stores only a single instance of multiple duplicate files. So if you have a WIM file with two Windows PE images, the files shared by the two images will be stored only once.
Note: Some applications, such as games, cannot run on Windows PE, but this is not the intended design of Windows PE. Windows PE currently does not support the Microsoft .NET Framework.
Flexible
If Windows Vista includes drivers for the computer hardware, your hardware will also be able to use Windows PE because Windows PE includes most Windows Vista drivers. You can also add new drivers to a Windows PE image. In an enterprise environment, you can add every driver required by any computer in your organization to a separate Windows PE image so that the image can be used with your computers.
For computers using special hardware, you can install a driver after Windows PE starts and immediately use the hardware without restarting the computer. For example, if you boot Windows PE and find that it does not contain the correct network driver, you can insert a CD containing the required driver and then use the Drvload command-line tool to inject the driver so that you can connect to the network. This feature is possible because Windows PE can run directly from the computer's RAM, as described later in this section.
Although Windows PE includes a large number of built-in features, many tools and features are optional to keep Windows PE as lightweight as possible. For example, WSH is not included in the standard Windows PE image. But if you need the WSH component to run scripts, it can be easily added. Similarly, you can add troubleshooting tools, such as Tracert or your own custom tools, to a custom Windows PE image. You can also use the same offline image editing tool to install updates and service packs to keep Windows PE up to date.
Most operating systems, such as Windows XP or Windows Vista, require running from the hard drive. You can boot Windows PE from a variety of boot media or network (for example, using WDS). Windows PE supports X86, X64, and IA64 architectures, so you can use the same pre-installation and troubleshooting environment for all computers in your organization. Windows PE can connect to both IPv4 networks (used by most organizations and on the Internet) and IPv6 networks. The boot settings of Windows PE can be changed by editing the text-based Unattend.xml file.
Although you can run Windows PE directly from the hard drive or removable media, you can also choose to run it directly from memory. If you choose to run Windows PE from memory, the Windows PE boot loader will first create a virtual RAM disk in memory. Then, the boot loader copies the compressed version of Windows PE to the RAM disk. Finally, the boot loader mounts the RAM disk as if it were a disk drive and starts Windows PE. Loading Windows PE from RAM provides additional flexibility because you can remove the Windows PE media after Windows PE starts. Therefore, you can load Windows PE from a CD and then replace that CD with a second CD containing tools or drivers. When running Windows PE from memory, it supports writing temporary files to the virtual RAM disk, which is not possible with read-only media, such as a CD.
Limitations of Windows PE
Because Windows PE is designed to be as lightweight, powerful, and flexible as possible, it has the following limitations:
• The computer must have a minimum of 256 MB of RAM.
• Windows PE is not suitable for providing on a floppy disk, but you can write the Windows PE image to a bootable CD.
• Windows PE requires a "Video Electronics Standards Association" (VESA) compatible display device and will use it to determine the highest supported screen resolution. If Windows PE cannot detect the video settings, it will use a resolution of 640 × 480 pixels.
• Windows PE only supports "Distributed File System" (DFS) name resolution for independent DFS roots.
• You cannot access files or folders on a computer running Windows PE from another computer. In other words, Windows PE does not provide server functionality.
• Windows PE supports both IPv4 and IPv6, but it does not support other protocols, such as the Internetwork Packet Exchange/Sequenced Packet Exchange (IPX/SPX) protocol.
• Drive letter assignment between sessions is not fixed. After restarting Windows PE, drive letters are assigned in the default order.
• Windows PE does not support the .NET Framework.
• Because Windows on Windows (WOW) is not supported, 16-bit applications cannot run in the 32-bit version of Windows PE, and 32-bit applications cannot run in the 64-bit version of Windows PE.
• To prevent Windows PE from being used as a general-purpose operating system, Windows PE will automatically restart after 24 hours of the initial boot loader start.
In addition, Windows PE only has a subset of the Windows Vista Win32 application programming interface (API), including I/O (disk and network) and core Win32 APIs. Applications that require any of the following Win32 APIs will not run in Windows PE: access control, NetShow Theater Administration, OpenGL, power management options, printing and print spooler system, still image, tape backup, terminal services, user profiles, Windows stations and desktops, Windows multimedia, and Windows shell.
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Comparison of Windows PE 2.0 with Early Technologies
If you have ever used MS-DOS or previous versions of Windows PE as a deployment or troubleshooting tool, you may be interested in how Windows PE improves these technologies. The following sections discuss how Windows PE improves the use of MS-DOS or previous versions of Windows PE.
Comparison of Windows PE 2.0 with MS-DOS Boot Disks
You can use Windows PE instead of an MS-DOS boot disk to perform the following tasks and complete them more smoothly in less time:
• Creating and formatting disk partitions, including NTFS file system partitions. Windows PE allows you to format a disk with the NTFS file system without using a third-party utility. Moreover, the file system utilities provided by Windows PE are scriptable, so you can fully automate partitioning and formatting.
• Accessing network shares to run troubleshooting tools and install the operating system. Windows PE provides network client functionality similar to Windows Vista. In fact, the network drivers provided by Windows PE are the same as those included with Windows Vista, allowing you to quickly and easily access the network. In contrast, customizing an MS-DOS boot disk to access network shares is always time-consuming and tedious.
• Loading and accessing 32-bit and 64-bit device drivers for audio, video, motherboard chipset, battery, and other devices that use Windows Vista drivers. Windows PE provides the ability to load Windows mass storage, network connections, audio, video, and other types of drivers. With MS-DOS, you would have to find 16-bit drivers, customize an MS-DOS boot disk, and maintain different disks for different network adapters.
• Automating tasks. The scripting capabilities in Windows PE far exceed those of MS-DOS boot disks. For example, Windows PE uses VBScript, a powerful scripting language that is easier to use than MS-DOS batch files. Windows PE supports gigabytes of memory on the system it runs on and provides network connection support using a protected-mode "Transmission Control Protocol/Internet Protocol" (TCP/IP) stack. You can easily add startup scripts or applications by editing a text-based "Extensible Markup Language" (XML) file. If you have already created scripts for MS-DOS, you might be able to use them in Windows PE; otherwise, you can easily import existing MS-DOS-based scripts into Windows PE.
• Running Win32 applications. One disadvantage of using MS-DOS as a pre-installation and operating system troubleshooting tool is that you can only run applications written specifically for MS-DOS. Because Windows PE supports most important Microsoft Win32 APIs, Windows PE can run most graphical and console-based Windows applications. Additionally, because Windows PE supports multithreading and multitasking, you can run multiple tools simultaneously.
Comparison of Windows PE 2.0 with Previous Versions of Windows PE
For many Microsoft customers, Windows PE 2.0 will be the first environment they adopt. But if you have used Windows PE 1.0, you may be interested in learning how Windows PE 2.0 improves. This section discusses the obvious improvements to Windows PE 1.0 for existing Windows PE users.
First, Windows PE 2.0 is based on Windows Vista components, while earlier versions of Windows PE were based on Windows XP or Microsoft Windows Server 2003. Therefore, Windows PE 2.0 supports Windows Vista drivers and benefits from many improvements in Windows Vista, including improvements in network attack prevention provided by Windows Firewall. As mentioned earlier, Windows PE 2.0 now supports driver injection, which allows you to load drivers before or after starting Windows PE. Now, if you boot Windows PE and find that it is missing a required driver, you can load a non-standard driver from a removable media and immediately use the hardware without restarting the computer.
For greater flexibility, especially when creating pre-installation scripts, Windows PE 2.0 now includes enhanced "Windows Management Instrumentation" (WMI) support. Using WMI, you can perform most configuration or management tasks via scripts or the command prompt. For more information about WMI, visit http://msdn.microsoft.com/library/en-us/dnanchor/html/anch_wmi.asp.
In the past, many applications could not run in Windows PE 1.0 because these programs required temporary storage space and Windows PE often booted from a non-writable media, such as a CD. Now, by providing 32 MB of burn space in the computer's RAM, Windows PE 2.0 can support most applications that need to perform write operations on temporary files. Whenever an application attempts to write to a temporary file (regardless of which folder), Windows PE redirects the changes to the burn space in memory to simulate a hard drive. Of course, all changes are lost when you restart the computer.
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Summary
Windows PE is a boot tool based on Windows Vista components. Unlike Windows Vista, Windows PE is not a general-purpose operating system but is dedicated to the installation, troubleshooting, and recovery of Windows Vista. Although every Windows Vista installation relies on Windows PE, the average user will never know that Windows PE exists.
However, IT departments can customize and extend Windows Vista to improve the efficiency of deployment and troubleshooting. In terms of deployment, IT departments can add custom components, drivers, and languages to Windows PE to meet their specific needs. They can also automate configuration and installation tasks to generate a custom, automated Windows Vista deployment or upgrade process.
In terms of troubleshooting, when Windows Vista fails to start normally, Windows PE will replace the MS-DOS boot disk for troubleshooting. In fact, if Windows Vista fails to boot, Windows PE will automatically load and start the "Windows Recovery Environment". IT departments can also use Windows PE for manual troubleshooting and can utilize built-in tools or add tools to the Windows PE image.
Windows PE plays an important part in the efficiency and reliability that Windows Vista provides to your IT infrastructure. Microsoft makes the most of Windows PE with the goal of providing a lightweight, powerful, and flexible specialized tool for pre-installation configuration and troubleshooting.
Overview of Windows PE 2.0 for Windows Vista
Publisher: Tony Northrup
Windows PE 2.0 is the core deployment foundation of Windows Vista. It is designed to make large-scale custom deployment of the new Windows Vista operating system particularly easy. When Windows Vista starts, all Windows Vista corporate customers will have access to Windows PE 2.0. (Windows PE for Windows XP remains exclusive to customers with Microsoft's "Software Assurance" (SA) agreement.) Windows PE allows users to inject drivers, configure Windows Vista offline, provide recovery solutions, and diagnose and troubleshoot system problems.
In February 2006, a pre-release version of Windows PE 2.0 generated for Windows Vista will be available for download and testing for all corporate customers participating in the Windows Vista pre-release program.
Summary
Microsoft Windows Preinstallation Environment (Windows PE) 2.0 provides powerful preparation and installation tools for the Windows Vista operating system. With Windows PE, you can boot a subset of Windows Vista from a network or removable media, providing the network and other resources necessary for installing and troubleshooting Windows Vista. This article describes Windows PE, its features, and improvements over earlier pre-installation technologies.
Page Content
Introduction
Installing with Windows PE
Troubleshooting with Windows PE
Windows PE Technology
Comparison of Windows PE 2.0 with Early Technologies
Summary
Introduction
Microsoft Windows Pre-installation Environment (Windows PE) 2.0 is a boot tool developed by Microsoft that provides operating system functionality for installation, troubleshooting, and recovery. Windows PE is not a general-purpose operating system but is dedicated to three specific tasks:
• Installing Microsoft Windows Vista. Every time Windows Vista is installed, Windows PE runs. During the installation phase, graphical tools that collect configuration information run within Windows PE. Additionally, information technology (IT) departments can customize and extend Windows PE to meet their unique deployment needs.
• Troubleshooting. Windows PE also helps with automatic and manual troubleshooting. For example, if Windows Vista fails to start due to a corrupted system file, Windows PE can automatically start the "Windows Recovery Environment". You can also manually start Windows PE to use built-in or customized troubleshooting and diagnostic tools.
• Recovery. "Original Equipment Manufacturers" (OEMs) and "Independent Software Vendors" (ISVs) can use Windows PE to create custom, automated solutions to recover and regenerate computers running Windows Vista. For example, users can boot their computers from a Windows PE recovery CD or recovery partition to automatically reformat their hard drive and reinstall Windows Vista with original drivers, settings, and applications.
This article is intended for IT professionals and describes the installation and troubleshooting features of Windows PE but does not discuss how OEMs and ISVs use Windows PE for recovery.
Basically, creating a standardized method that administrators can use to effectively track problem areas and make repairs saves valuable time spent interpreting complex error logs. Administrators can use the information in this article as tools and checklists to reduce the time spent on resolving failed connections. It can also help administrators solve their own problems before seeking help from "Microsoft Product Support Services".
Note: Since Windows PE is specifically designed as a tool for configuring, installing, and troubleshooting Windows Vista, Windows PE cannot be purchased separately from Windows Vista.
Back to Top
Installing with Windows PE
Microsoft has designed Windows PE as a pre-installation environment to replace MS-DOS. Windows PE is built on top of Windows Vista components, providing a powerful, flexible, and familiar environment. In fact, Windows PE can run many Windows Vista applications, detect and enable most modern hardware, and communicate over the "Internet Protocol" (IP) network. Windows PE typically occupies less than 100 MB of disk space and can run entirely from "Random Access Memory" (RAM), allowing you to insert a second CD containing drivers or software for use. These features enable Windows PE to run on computers with currently unformatted hard drives or no operating system installed. However, unlike Windows Vista, Windows PE is not a fully functional operating system.
Customizing Windows Vista Installation
Nonetheless, enterprises will appreciate the emergence of Windows PE because IT departments will be able to create scripts and applications to automate deployment. For example, an IT department can use the following process to configure a "Windows Deployment Services" remote deployment infrastructure, create a configuration script, and generate a custom Windows PE image to enable a highly automated deployment process:
1.
When a new computer connects to the network, the built-in "Pre-Boot Execution Environment" (PXE) client connects to the "Windows Deployment Services" server and downloads the custom Windows PE image over the network.
2.
The new computer loads Windows PE into memory and starts the configuration script. The script verifies that the computer's configuration meets the IT department's hardware requirements.
Note: "Windows Deployment Server" (Windows DS) replaces "Remote Installation Services" (RIS).
3.
If necessary, the script backs up user data to a shared folder on another computer.
4.
The script runs the Diskpart tool to partition and format the disk.
5.
The script connects to a shared folder containing "Windows Vista Installation" files and runs the "Windows Vista Installation" program to install the operating system in completely unattended mode.
Windows PE and Windows Image Format
The most powerful and flexible way to distribute Windows PE is by using the "Windows Image Format" (WIM) file. WIM is a file-based image format that Windows Vista uses for fast installation on new computers. A WIM file stores copies (called images) of one or more operating systems, such as Windows Vista or Windows PE. Maintaining an operating system using a WIM file is easy because you can add and remove drivers, update content, and Windows components offline without booting the operating system. Maintaining a Windows PE image using a WIM file is very similar to maintaining a Windows Vista image.
Similar to Windows Vista, Windows PE can be included in a WIM file. But when you store a Windows Vista image in a WIM file, the only way to boot Windows Vista is to copy the image to the computer's hard drive. However, Windows PE can boot directly from a WIM file that has not been copied to the hard drive. This feature allows you to create a WIM file and store it on a bootable media, such as a CD or USB flash drive, and then boot Windows PE directly from that media. When installing Windows Vista on a new computer, Microsoft uses this feature to load Windows PE into RAM and start Windows PE.
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Troubleshooting with Windows PE
Although the main use of Windows PE is to install Windows Vista, you can also use Windows PE for troubleshooting. Examples of troubleshooting tasks include:
• Replacing system files. You can replace corrupted files on the original installation media. For example, if a corrupted system file prevents the computer from booting, you can use Windows PE to start the computer and then replace the corrupted file in the Windows Vista media.
• Restoring data before reinstalling Windows. Windows PE provides full access to FAT and NTFS file systems. In cases where you must replace or reformat the hard drive, you can first boot the computer with Windows PE and then copy important files to another disk or shared folder. Note that files encrypted with the "Encrypting File System" (EFS) are not easily recoverable.
• Running diagnostic and configuration tools. Windows PE includes common command-line diagnostic tools. You can also run other standard and custom Windows troubleshooting tools within Windows PE. Built-in tools include:
• Diskpart. Diskpart is a text-mode command interpreter that allows you to manage disks, partitions, or volumes via the command prompt or scripts.
• Drvload. You can use the drvload command to add device drivers (such as audio, video, and motherboard chipset) to the Windows PE image. You can also use drvload to dynamically load drivers after Windows PE has started.
• Net. The Net command-line tool allows you to manage the local user database, start and stop services, and connect to shared folders.
• Netcfg. This network configuration tool configures network access. When using Windows PE as a custom deployment tool, you might use Netcfg to manually configure network settings as part of a boot script.
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Windows PE Technology
To make Windows PE as universal as possible, Microsoft has designed it to be lightweight, powerful, and flexible. The following sections describe these features in more detail, followed by a description of the limitations of Windows PE.
Lightweight
Windows PE must be as small as possible to be stored on removable media, such as CDs and USB flash drives, and must be able to start quickly and run entirely from the computer's memory. The exact size of Windows PE varies depending on how the image is customized, but when compressed in WIM format, it typically occupies less than 100 MB of space. The 64-bit version of Windows PE is larger, and customizing the Windows PE image with language packs or applications increases its size.
To help minimize memory usage, run Windows PE from a compressed image. In other words, you can compress Windows PE within a WIM file and run it from memory without decompressing it. Therefore, you benefit from compression both when storing the image on disk and after loading it into the computer's memory.
To minimize disk storage, the WIM format stores only a single instance of multiple duplicate files. So if you have a WIM file with two Windows PE images, the files shared by the two images will be stored only once.
Powerful
Although Windows PE is designed to be small, it contains a large number of core features of Windows Vista. Because Windows PE supports Win32 (just like Microsoft Windows XP and Windows Vista), most Windows applications can run in Windows PE. This means that developers in IT departments can use tools like Microsoft Visual Studio to create Win32 applications that run on Windows PE.
Windows PE also supports multithreading and multitasking, so you can run multiple tools simultaneously. This feature saves time and resources that would otherwise be needed to verify and test hardware and software images using other technologies. Windows PE can also run batch files, Microsoft Visual Basic Scripting Edition (VBScript) scripts, Windows Script Host (WSH) scripts (if the optional WSH component is installed), HTML applications (HTA), and Microsoft ActiveX Data Objects (ADO). Because Windows PE provides RAM-based temporary space, Windows PE can run applications that need to write temporary files to the hard drive (even if there is no available hard drive).
To minimize disk storage, the WIM format stores only a single instance of multiple duplicate files. So if you have a WIM file with two Windows PE images, the files shared by the two images will be stored only once.
Note: Some applications, such as games, cannot run on Windows PE, but this is not the intended design of Windows PE. Windows PE currently does not support the Microsoft .NET Framework.
Flexible
If Windows Vista includes drivers for the computer hardware, your hardware will also be able to use Windows PE because Windows PE includes most Windows Vista drivers. You can also add new drivers to a Windows PE image. In an enterprise environment, you can add every driver required by any computer in your organization to a separate Windows PE image so that the image can be used with your computers.
For computers using special hardware, you can install a driver after Windows PE starts and immediately use the hardware without restarting the computer. For example, if you boot Windows PE and find that it does not contain the correct network driver, you can insert a CD containing the required driver and then use the Drvload command-line tool to inject the driver so that you can connect to the network. This feature is possible because Windows PE can run directly from the computer's RAM, as described later in this section.
Although Windows PE includes a large number of built-in features, many tools and features are optional to keep Windows PE as lightweight as possible. For example, WSH is not included in the standard Windows PE image. But if you need the WSH component to run scripts, it can be easily added. Similarly, you can add troubleshooting tools, such as Tracert or your own custom tools, to a custom Windows PE image. You can also use the same offline image editing tool to install updates and service packs to keep Windows PE up to date.
Most operating systems, such as Windows XP or Windows Vista, require running from the hard drive. You can boot Windows PE from a variety of boot media or network (for example, using WDS). Windows PE supports X86, X64, and IA64 architectures, so you can use the same pre-installation and troubleshooting environment for all computers in your organization. Windows PE can connect to both IPv4 networks (used by most organizations and on the Internet) and IPv6 networks. The boot settings of Windows PE can be changed by editing the text-based Unattend.xml file.
Although you can run Windows PE directly from the hard drive or removable media, you can also choose to run it directly from memory. If you choose to run Windows PE from memory, the Windows PE boot loader will first create a virtual RAM disk in memory. Then, the boot loader copies the compressed version of Windows PE to the RAM disk. Finally, the boot loader mounts the RAM disk as if it were a disk drive and starts Windows PE. Loading Windows PE from RAM provides additional flexibility because you can remove the Windows PE media after Windows PE starts. Therefore, you can load Windows PE from a CD and then replace that CD with a second CD containing tools or drivers. When running Windows PE from memory, it supports writing temporary files to the virtual RAM disk, which is not possible with read-only media, such as a CD.
Limitations of Windows PE
Because Windows PE is designed to be as lightweight, powerful, and flexible as possible, it has the following limitations:
• The computer must have a minimum of 256 MB of RAM.
• Windows PE is not suitable for providing on a floppy disk, but you can write the Windows PE image to a bootable CD.
• Windows PE requires a "Video Electronics Standards Association" (VESA) compatible display device and will use it to determine the highest supported screen resolution. If Windows PE cannot detect the video settings, it will use a resolution of 640 × 480 pixels.
• Windows PE only supports "Distributed File System" (DFS) name resolution for independent DFS roots.
• You cannot access files or folders on a computer running Windows PE from another computer. In other words, Windows PE does not provide server functionality.
• Windows PE supports both IPv4 and IPv6, but it does not support other protocols, such as the Internetwork Packet Exchange/Sequenced Packet Exchange (IPX/SPX) protocol.
• Drive letter assignment between sessions is not fixed. After restarting Windows PE, drive letters are assigned in the default order.
• Windows PE does not support the .NET Framework.
• Because Windows on Windows (WOW) is not supported, 16-bit applications cannot run in the 32-bit version of Windows PE, and 32-bit applications cannot run in the 64-bit version of Windows PE.
• To prevent Windows PE from being used as a general-purpose operating system, Windows PE will automatically restart after 24 hours of the initial boot loader start.
In addition, Windows PE only has a subset of the Windows Vista Win32 application programming interface (API), including I/O (disk and network) and core Win32 APIs. Applications that require any of the following Win32 APIs will not run in Windows PE: access control, NetShow Theater Administration, OpenGL, power management options, printing and print spooler system, still image, tape backup, terminal services, user profiles, Windows stations and desktops, Windows multimedia, and Windows shell.
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Comparison of Windows PE 2.0 with Early Technologies
If you have ever used MS-DOS or previous versions of Windows PE as a deployment or troubleshooting tool, you may be interested in how Windows PE improves these technologies. The following sections discuss how Windows PE improves the use of MS-DOS or previous versions of Windows PE.
Comparison of Windows PE 2.0 with MS-DOS Boot Disks
You can use Windows PE instead of an MS-DOS boot disk to perform the following tasks and complete them more smoothly in less time:
• Creating and formatting disk partitions, including NTFS file system partitions. Windows PE allows you to format a disk with the NTFS file system without using a third-party utility. Moreover, the file system utilities provided by Windows PE are scriptable, so you can fully automate partitioning and formatting.
• Accessing network shares to run troubleshooting tools and install the operating system. Windows PE provides network client functionality similar to Windows Vista. In fact, the network drivers provided by Windows PE are the same as those included with Windows Vista, allowing you to quickly and easily access the network. In contrast, customizing an MS-DOS boot disk to access network shares is always time-consuming and tedious.
• Loading and accessing 32-bit and 64-bit device drivers for audio, video, motherboard chipset, battery, and other devices that use Windows Vista drivers. Windows PE provides the ability to load Windows mass storage, network connections, audio, video, and other types of drivers. With MS-DOS, you would have to find 16-bit drivers, customize an MS-DOS boot disk, and maintain different disks for different network adapters.
• Automating tasks. The scripting capabilities in Windows PE far exceed those of MS-DOS boot disks. For example, Windows PE uses VBScript, a powerful scripting language that is easier to use than MS-DOS batch files. Windows PE supports gigabytes of memory on the system it runs on and provides network connection support using a protected-mode "Transmission Control Protocol/Internet Protocol" (TCP/IP) stack. You can easily add startup scripts or applications by editing a text-based "Extensible Markup Language" (XML) file. If you have already created scripts for MS-DOS, you might be able to use them in Windows PE; otherwise, you can easily import existing MS-DOS-based scripts into Windows PE.
• Running Win32 applications. One disadvantage of using MS-DOS as a pre-installation and operating system troubleshooting tool is that you can only run applications written specifically for MS-DOS. Because Windows PE supports most important Microsoft Win32 APIs, Windows PE can run most graphical and console-based Windows applications. Additionally, because Windows PE supports multithreading and multitasking, you can run multiple tools simultaneously.
Comparison of Windows PE 2.0 with Previous Versions of Windows PE
For many Microsoft customers, Windows PE 2.0 will be the first environment they adopt. But if you have used Windows PE 1.0, you may be interested in learning how Windows PE 2.0 improves. This section discusses the obvious improvements to Windows PE 1.0 for existing Windows PE users.
First, Windows PE 2.0 is based on Windows Vista components, while earlier versions of Windows PE were based on Windows XP or Microsoft Windows Server 2003. Therefore, Windows PE 2.0 supports Windows Vista drivers and benefits from many improvements in Windows Vista, including improvements in network attack prevention provided by Windows Firewall. As mentioned earlier, Windows PE 2.0 now supports driver injection, which allows you to load drivers before or after starting Windows PE. Now, if you boot Windows PE and find that it is missing a required driver, you can load a non-standard driver from a removable media and immediately use the hardware without restarting the computer.
For greater flexibility, especially when creating pre-installation scripts, Windows PE 2.0 now includes enhanced "Windows Management Instrumentation" (WMI) support. Using WMI, you can perform most configuration or management tasks via scripts or the command prompt. For more information about WMI, visit http://msdn.microsoft.com/library/en-us/dnanchor/html/anch_wmi.asp.
In the past, many applications could not run in Windows PE 1.0 because these programs required temporary storage space and Windows PE often booted from a non-writable media, such as a CD. Now, by providing 32 MB of burn space in the computer's RAM, Windows PE 2.0 can support most applications that need to perform write operations on temporary files. Whenever an application attempts to write to a temporary file (regardless of which folder), Windows PE redirects the changes to the burn space in memory to simulate a hard drive. Of course, all changes are lost when you restart the computer.
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Summary
Windows PE is a boot tool based on Windows Vista components. Unlike Windows Vista, Windows PE is not a general-purpose operating system but is dedicated to the installation, troubleshooting, and recovery of Windows Vista. Although every Windows Vista installation relies on Windows PE, the average user will never know that Windows PE exists.
However, IT departments can customize and extend Windows Vista to improve the efficiency of deployment and troubleshooting. In terms of deployment, IT departments can add custom components, drivers, and languages to Windows PE to meet their specific needs. They can also automate configuration and installation tasks to generate a custom, automated Windows Vista deployment or upgrade process.
In terms of troubleshooting, when Windows Vista fails to start normally, Windows PE will replace the MS-DOS boot disk for troubleshooting. In fact, if Windows Vista fails to boot, Windows PE will automatically load and start the "Windows Recovery Environment". IT departments can also use Windows PE for manual troubleshooting and can utilize built-in tools or add tools to the Windows PE image.
Windows PE plays an important part in the efficiency and reliability that Windows Vista provides to your IT infrastructure. Microsoft makes the most of Windows PE with the goal of providing a lightweight, powerful, and flexible specialized tool for pre-installation configuration and troubleshooting.