Boot from VHD in Windows 7

A Virtual Hard Disk created in a VHD file in the hard disk will acts as a separate hard drive in the computer.

You can attach a VHD file to your computer and use the contents of the VHD as in a separate hard drive partition. And you can use the OS installed on the VHD as dual boot OS and make use of the maximum of your machine without creating a physical partition on the hard disk and installing an OS. Thus enjoying the benefits of the Windows 7 feature – Boot from VHD.

Let’s see how it can be done, it’s pretty simple.

Step 1: Attach a VHD

Open the Computer Management console by either right clicking on the Computer item on the Start Menu or typing compmgmt.msc in the Search box in the Start Menu and Enter.

From the left pane of the Computer Management console, select Disk Management and select the Attach VHD item on the Action menu.

Click the Browse button on the new window opened and select the VHD file.

That’s all; you now attached a VHD.

Step 2: Make the VHD Bootable

Open an Elevated Command prompt by typing cmd in the Start Menu search box area, then right click on cmd, and click on Run as administrator.

In the cmd window, go to the drive letter of the VHD attached and change drives to the \windows\system32 directory.

Type the following command and press Enter:

bcdboot w:\windows

(Note: Assuming that W is the drive letter of the newly created partition while attaching the VHD)

Execute the following command to make your current OS as your default boot OS:

bcdedit /default {current}

Tips:  If you created multiple boot, system like above, then you can see the boot control data (bcd) by executing the following command:

bcdedit /v

Also, if you want to make any of the OS as your default boot OS, which can be done by executing the following command:

bcdedit /default {identifier}

(Note: The identifier can be found by executing bcdedit /v command)

That’s all, now the your boot from VHD setup is ready, restart the system, then you can see the multi-boot menu loaded on the screen, now you have too many OS options to load.

Also, if you want to create a new VHD on your own, Microsoft Virtual PC can help you.

This feature is supported only by Windows 7 Ultimate and Enterprise versions only.

Also, if somebody wants to remove the Boot option created, can be done by executing msconfig utility.

Virtualization with Windows7

Windows 7 virtualization includes running Windows 7 as either a host OS (Operating System) or a guest OS (virtual OS). When you run Windows 7 as the host OS, you can run another operating system, such as Windows XP or Linux, within it as its guest OS. When you run another OS, such as Mac OS X Snow Leopard, as the host OS, you can run Windows 7 within it as its guest OS.

Support for these technologies is not across the board, however. Intel-VT can be found in some very old Pentium 4 models – the 662 and 672 – but not in certain Core 2 processors. There are even some Atom chips with –VT, but not all Pentium-D processors. The Core 2 family is quite varied, according to this Intel product list.

In the case of AMD, it introduced AMD-V in 2006 with the Athlon 64 and Athlon 64 X2 with family "F" or "G" on socket AM2. Earlier generations of AMD chips that used the Socket 939 do not include AMD-V. The "Sempron" family also does not support AMD-V.

Windows 7 has a new feature that makes it easier than ever to set up multi-boot scenarios on a single machine.
Boot from VHD allows you to mount a vhd as a bootable drive and, as the name implies, boot from it.  It's a great scenario for creating multiple OS installations without having to create multiple OS partitions on your hard drive.

In Windows 7, native VHD boot allows you to create and modify VHD files without installing the Hyper-V server role. You can attach VHD files by using the disk management tools, and you can service the Windows image inside the VHD. You can use the deployment tools in the Windows Automated Installation Kit (Windows AIK) to apply a Windows image to the VHD and to apply updates to the image in the VHD file.

Native VHD boot also requires the Windows 7 boot environment. The Windows 7 boot environment is initialized during a full operating system installation, and it includes the Windows Boot Manager, Boot Configuration Data (BCD), and other supporting files.

More details will be updated soon.