After creating a custom Windows® Preinstallation Environment (Windows PE) image, you must decide how the image will boot and where it will run from.
There are five methods of starting Windows PE by using a RAM disk. You can create bootable Windows PE RAM disk images on:
- CD-ROM and DVD-ROM.
- A USB flash drive (UFD).
- A hard disk.
- A Windows Deployment Services
(Windows DS) server. You can access the image by using
Pre-Boot Execution Environment (PXE) boot.
- A supported PXE server. You can access the
image by using PXE boot.
Normally, when you start a computer from a hard disk drive or a CD-ROM, Windows keeps operating-system file handles open and dedicated to that instance of Windows. Therefore, you cannot remove the CD that you used to start the computer. You cannot delete the hard disk partition from which you started the computer.
The small size of Windows PE enables the entire Windows PE operating system image to load into random access memory (RAM) and to start the computer from a RAM disk. The RAM disk boot feature provides a virtual CD file system in memory. Booting Windows PE from a RAM disk enables you to:
- Swap the removable media (CD-ROM or DVD-ROM)
that is used to start the computer and insert another CD-ROM or
DVD-ROM to add drivers, utilities, applications, or a Windows
operating system image.
- Start the computer from a
Windows Deployment Services (PXE) server with the ability to
disconnect from the network once Windows PE has loaded. After
the initial download of the Windows PE image, there are no
longer any dependencies on network resources.
- Delete and repartition the hard disk from
which Windows PE has just started.
- Decrease total boot time.
- By default, Windows PE assigns X as the
drive letter of any media that it boots from. You can change the
drive location using DISM /Set-TargetPath.
- For Unified Extensible Firmware Interface
(UEFI)-based computers, you must start Windows PE by using the
EFI boot-mode option in the EFI shell. For more information, see
your EFI firmware documentation.
- By default, Windows PE assigns X as the drive letter of any media that it boots from. You can change the drive location using DISM /Set-TargetPath.
The following items are required for starting Windows PE by using a RAM disk:
- An x86-based, x64-based, or Itanium-based
- A bootable Windows PE image created from
a Windows PE 3.0 base image.
- A minimum of 512 megabytes (MB) of RAM
(when using the default Windows PE disk image).