What the heck is a DISM any way? The short answer is “yes”. Simply put, DISM is the new, improved version of ImageX.
What is DISM?
ImageX and therefore DISM (Deployment Image Service and Management tool) is Microsoft’s native, command line based imaging tool and is used to create, edit and deploy disk images in the Windows Imaging Format (WIM). WIM files are mounted and serviced (edited) and then dismounted for application to a physical or virtual disk. The benefits of the WIM format include the ability to edit the OS in an “offline” or not-currently-running state and the ability to include multiple OS images in the same file without bloat from multiple, identical files.
ImageX released with Windows Vista as part of the Windows Automated Installation Kit (WIAK) and continued in use through Windows 7. Microsoft Deployment Image Servicing and Management (DISM), ImageX’s replacement, was released with Windows 8 as part of the Windows Assessment and Deployment Kit (WADK) and will be upgraded, not replaced, with the release of Windows 8.1. ImageX had been deprecated as of the release of Windows 8.
Where does Windows Pre-Installation Environment (Windows PE) come in to play?
Windows PE or WinPE is the utility (stripped down and much smaller) version of Windows operating system that ImageX or DISM is executed to achieve image creation, editing, or deployment.
ImageX -> Windows Vista & Windows 7 (WAIK) + Windows PE v3.0 or v3.1
DISM -> Windows 8 (WADK) + Windows PE v4.0 (v4.1 with Windows 8.1)
Various hardware requirements are necessary to successfully instantiate a WinPE v4.x session. The requirements specific to hardware (processor) for WADK (v4.0 and 4.1) include support for the following:
Physical Address Extension (PAE), NX processor bit (NX), and Streaming SIMD Extensions 2 (SSE2) are features of the processor, and they're needed to run Windows 8.0 or 8.1.
- PAE gives 32-bit processors the ability to use more than 4 GB of physical memory on capable versions of Windows, and is a prerequisite for NX.
- NX helps your processor guard the PC from attacks by malicious software.
- SSE2 is a standard instruction set on processors that is increasingly used by third-party apps and drivers.
If your PC doesn't support PAE, NX, and SSE2, you won’t be able to install Windows 8.0 or 8.1
If the processors of machines targeted for deployment do not meet the aforementioned processor requirements, deployment tools will not be able to affect those target machines and therefore users must also install Windows Automated Deployment Kit (WAIK v3.0) on their administration machine.
How do I get DISM?
As alluded to previously, the DISM tool is made available by Microsoft in the Windows Assessment and Deployment Kit (WADK) just as the ImageX tool is made available in the Windows Automated Installation Kit (WAIK).
Even if a user has determined that their older hardware requires a version of Windows PE older than the one supplied in WADK and opted to also install WAIK for that purpose, and the older Windows PE (version 3.x) can be used to boot the target PC, and the DISM commands can be used to deploy a WIM image.
Differences in Syntax
Although the function of DISM is identical in most respects to ImageX, there are notable differences in syntax or command line format. That said, those familiar with ImageX will not have any trouble deciphering the DISM commands. Below are the same “apply image” function formatted for both ImageX and DISM. The similarities are obvious:
ImageX: ImageX /apply <image file path> <index number> <drive letter>
DISM: DISM /apply-image /imagefile:<image file path> /index:1 /applydir:<drive letter>
How do I use DISM to deploy an OS image?
There are three basic steps by which an operating system image may be deployed using DISM:
Target PC preparation
First, the target PC will need to be formatted and partitioned, using a tool named DISKPART, in order to accept a Windows image. An example of a simple DISKPART script file is illustrated below.
select disk 0
create partition primary
format quick fs=ntfs label="Windows"
There may be additional partitions created to support UEFI (as opposed to GPT) including Windows RE Tools, System, and Recovery partitions.
Next, the image must be extracted from the WIM file and applied to the partition designated for Windows during DISKPART.
DISM /apply-image /imagefile:<image file path> /index:1 /applydir:<drive letter>
Boot file creation
Lastly, a boot entry must be made in order to boot to the applied Windows image using a tool named BCDBOOT (Boot Configuration Data editor).
If you’ve used ImageX in the past (or still do), the introduction of Windows 8 will most certainly encourage you to familiarize yourself with the DISM tool and update your image creation and deployment processes. Don’t worry, it’s not that much different!