Managing Your Operating Systems
Operating System Images In Desktop Deployment
The operating system images deployed to your desktop computers are an essential component in desktop deployment. These images are the blueprint that describes the configuration of your computers after your desktop deployment process is complete.
The Solution Accelerator for Business Desktop Deployment (BDD) Enterprise Edition and Solution Accelerator for Business Desktop Deployment Standard Edition offer many products and technologies that you can use to deploy operating system images to the computers in your organization. Table 1 lists the technologies for deploying images and describes the role of these methods in the Solution Accelerator for BDD Enterprise Edition and Standard Edition.Table 1. Image Deployment Methods and Their Role in the Solution Accelerators
Role in Solution Accelerator for BDD Enterprise Edition and Standard Edition
Operating System Deployment (OSD) feature pack in Microsoft® Systems Management Server 2003
OSD is used in the Solution Accelerator for BDD Enterprise Edition to deploy Microsoft Windows® XP images through Zero Touch Installation (ZTI) or Lite Touch Installation (LTI). Note that OSD is part of Systems Management Server 2003 rather than Solution Accelerator for BDD.
Remote Installation Service (RIS)
RIS is used to start Microsoft Windows Preinstallation Environment (Windows PE). Windows PE is used to prepare desktop computers for Windows XP deployment.
Sysprep is used in the Solution Accelerator for BDD Enterprise Edition in instances in which ZTI is unavailable to clients (such as for remote users with laptop computers that rarely connect to the organization’s intranet). In the Solution Accelerator for BDD Standard Edition, Sysprep is used as the primary imaging method for the Windows XP operating system in desktop deployment, because Systems Management Server 2003 and OSD are not a part of that Solution Accelerator for BDD edition.
Each of these technologies requires a different image format that you must create and maintain. For example, if you are going to deploy the Windows XP operating system by using OSD and RIS, create one image for OSD-based deployments and another image for RIS-based deployments.
How Operating System Images Are Used
Ultimately, OSD, RIS, and Sysprep accomplish the same goal—that is, expanding an operating system onto the local hard disk drive of a desktop computer. However, each method expands an operating system onto the hard disk drive in slightly different ways. Table 2 lists each method and shows how that method expands the operating system images.Table 2. Image Deployment Methods and How They Use the Operating System Images
How This Method Uses the Operating System Images
OSD images are prepared from within Systems Management Server Administrator through a wizard. The wizard prompts you for a source directory, then creates a deployment image based on that directory. Subsequently, you can deploy the image to Systems Management Server distribution points, where Systems Management Server clients can expand the image onto the local disk drive of the target computer.
RIS images are created in folders on the RIS server. RIS responds to Pre-Boot eXecution Environment (PXE) boot requests from integrated PXE support on the desktop motherboard, on the network adapter, or by booting from a PXE boot disk. The PXE boot request process expands the image onto the local disk drive of the target computer.
Sysprep images are created by configuring a computer to your organization’s standards, and then running Sysprep to prepare the disk image for duplication. You can burn the disk image onto a CD-ROM or DVD-ROM or store the image in a shared folder. Then, you can expand the image onto the local disk drive of the target computer.
As you can tell from this table, none of these methods allows you to easily share the final images, and each method requires its own format. However, you could use a common set of source files to create OSD and RIS images. Because Sysprep is based on an image of an actual desktop, no source files are used. To reduce your image management effort, you should create the images for OSD and RIS by using the same set of source files whenever possible.
What Makes Operating System Images Unique
Based on the previous discussion, you would think that there shouldn’t be too many images to maintain. I’ve talked about needing separate images for RIS, OSD, and Sysprep. Unfortunately, other factors can require that you create additional images.
A unique image will be required for each of the following:
Unique Hardware Abstraction Layer (HAL) type. Each target computer requires a HAL that is suitable for the computer hardware, including 32-bit or 64-bit processors, as appropriate .To ensure that you deploy the right image, with the correct HAL, to the target computer, create and maintain a separate image for each HAL in your organization.
Localized versions of the operating system. Some users require versions of the operating system in their native language instead of using multilingual versions. Ensure that you deploy the correct language to the target computer.
Localized versions of applications running on multi-user interface (UI) versions of the Windows XP operating system. Some users require that applications be in their native language regardless of the fact that the operating system may be multilingual. Deploy the correct language of these applications to the target computer.
Unique set of hardware device drivers. Different computer models require different hardware device drivers, and you need to incorporate these drivers in the image you deploy to the target computers. In some instances, combining all the device drivers into one image may make the image too large. In this instance, you need to customize the image with the correct set of device drivers.
Unique set of applications with an organization. Different users or business units within your organization may need different sets of applications. Combining all your organization’s applications into one image may make the image too large. In most instances, not all users need access to all applications. As a result, you may need to create multiple images based on user roles or business unit.
Multiple customers (for consultant organizations, service providers, or hosting organizations). Each customer may require unique applications, customized desktop configurations, or have other organization-specific issues. In addition, you may be contractually bound not to share any images, files, or resources between your customers.
Different security requirements. Different business units or groups of users may have different security requirements. These security requirements may demand that you include (or exclude) unique sets of configuration settings or files in the images.
Strategies for Consolidating Images
With all the factors that require unique images, the permutations of those factors can dramatically increase the number of images required in your organization. You need to address these factors, yet reduce the number of images you’re supporting.
Consider using the following strategies to consolidate the number of images required in your organization:
Use multilingual versions of operating systems. Multilingual versions of the Windows XP operating system can help you create fewer images that can address multiple language requirements.
Use multilingual versions of applications. Multilingual versions of your applications (such as Microsoft Office 2003) can help you create fewer images that address multiple language requirements.
Include multiple HAL types in an image. You can put multiple HAL types in one image, use a script to help you determine the HAL type of the target computer, and then use the appropriate HAL in the image (this is required for images you use Sysprep to build).
Include all necessary device drivers in one image. Group as many device drivers as possible into one image while maintaining a reasonable image size. You can then deploy one image to multiple computer types.
Customize the set of applications to be installed after operating system deployment. When your application requirements are too diverse, consider automatically deploying the applications after the operating system. In this way, you can reduce the number of operating system images.
Strategies for Storing Images
After you’ve created your images, managing the storing of the images becomes an ongoing process. The ultimate goal is to reduce the number of instances of each image. Ideally, you would have one copy of each image in your infrastructure. However, that may not be possible because of geographic and network bandwidth availability issues.
Consider the following strategies for storing your images:
Allow read-only access to the images from non-administrative-level users.
Use a consistent naming convention that allows you to easily identify the image and the target computers the image services.
Deploy from one source for multiple methods. For example, deploy a target computer by using a boot disk or CD to connect to an image on a Systems Management Server distribution point in addition to deploying the image through Systems Management Server.
Managing More Computers with Fewer Images
Now that you have reduced the number of images in your initial deployment, you need to ensure that the number stays small during your ongoing maintenance. Incorporate change management procedures and processes to make sure that no unplanned (and unnecessary) images are created.
In the long term, consolidate the methods that you use for deploying computers. For example, if you are currently using OSD, RIS, and Sysprep to deploy computers, try to eliminate one of the three methods.
Reducing the number of images is an ongoing process. But the benefits result in faster deployments with fewer configuration errors and a reduction in lost user time. By starting today, you can reap the benefits of fewer deployment images in your next deployment—and be on the road to a more manageable deployment environment.
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About the Author
Douglas Steen is an architect, consultant, technical trainer, and author who focuses on Microsoft products and integration technologies. Doug has been designing and creating hardware and software solutions since 1975 and has written several training courses, books, and online articles. Most recently, Doug wrote most of the IIS 6.0 Deployment Guide for Microsoft Press, a series of white papers for Microsoft about Active Directory, and portions of the Solution Accelerator for Business Desktop Deployment Enterprise Edition. You can contact Doug at firstname.lastname@example.org.