You can only copy a disk image onto a destination computer if the HAL on the disk image is compatible with the HAL on the destination computer. Compatible HALs are those that are identical or those that can be updated during an image-based installation. If the HAL on your disk image is not compatible with the HAL that is required on a destination computer, you need to create a separate disk image for the HAL that is required on the destination computer. Table 3.2 can help you determine which HALs are compatible.

Caution

• Copying a disk image to a destination computer that has an incompatible HAL can cause the destination computer to restart continuously, become unresponsive, or generate Stop errors.
  

Using the information in your hardware inventory, you can determine whether you need more than one disk image for each operating system based on your HAL requirements. For example, if you are installing Windows Server 2003, Standard Edition on 50 computers, 10 of which require a non-ACPI HAL and 40 of which require an ACPI HAL, you need to create two disk images of Windows Server 2003, Standard Edition: one image for the ACPI HAL and one image for the non-ACPI HAL.

Use the following guidelines to determine how many disk images you need based on the HALs used in your organization:

• PIC and APIC HALs are not compatible: You need one disk image for computers that require PIC HALs and one disk image for computers that require APIC HALs.
  
• ACPI and non-ACPI HALs are not compatible: You need one disk image for computers that require ACPI HALs and one disk image for computers that require non-ACPI HALs.
  
• Non-ACPI APIC uniprocessor HALs and non-ACPI APIC multiprocessor HALs are compatible: You can use a single disk image for all computers that require these HALs.
  
• ACPI APIC uniprocessor HALs and ACPI APIC multiprocessor HALs are compatible: You can use a single disk image for all computers that require these HALs.
  
• ACPI PIC HALs are not compatible with any other HAL: You need a separate disk image for computers that require ACPI PIC HALs.
  

In addition, you might need to have a separate disk image if any of your computers support hyper-threading. Hyper-threading enables multithreaded software applications to execute threads in parallel within each processor. On a hyper-threading enabled system, Windows XP and the Windows Server 2003 family function as they would on a multi-processor system, even when only a single physical processor is installed.

Windows automatically uses the hyper-threading capabilities of the processor if the following conditions are met:

• The computer hardware supports hyper-threading, and this functionality is enabled in the computer’s BIOS.
  
• Hyper-threading functionality is installed in the computer processor.
  
• The computer is using an ACPI Uniprocessor HAL.
  
• Windows detects one or more processors or enabled threads.
  

When the listed conditions are met, Windows automatically updates the HAL to the ACPI Multiprocessor HAL and installs an additional processor.

When a disk image is copied to a hyper-threading-enabled system, and the HAL is incompatible, the computer might not boot correctly. If the computer does boot correctly, it might not be able to take advantage of hyper-threading technology.

To ensure that the HALs on your disk images are compatible with hyper-threading enabled systems, you must create the master installation on a computer that has one of the following:

• An ACPI hyper-threading enabled HAL.
  
• An ACPI APIC uniprocessor HAL.
  
• An ACPI multiprocessor HAL.
  

If you do not create the master installation on one of these types of computers, Windows is not able to update the system to use multiple processors. A Sysprep image made on an ACPI-compliant multiprocessor computer will run in a multiprocessor configuration even if support for hyper-threading is turned off in the BIOS.

In each copy of the job aid "Disk Image Worksheet " (ACISYS_1.doc), under "Hardware Installed on this Image," enter the type of HAL that will be included on the disk image. You might have to create more copies of the worksheet if you are deploying several different types of HALs with the same operating system and the HALs are incompatible. Be sure to include the file name of the HAL in the worksheet. HAL file names and descriptions are listed in Table 3.2.

You might also need to create a separate disk image for portable computers. Portable computers often require vendor-specific or hardware-specific device drivers. Frequently, these specialized device drivers are not compatible with desktop computers. For example, if you configure a disk image of a portable computer that has an inboard pointing device, and then copy the disk image onto a desktop computer, the desktop computer might not have mouse or keyboard support.

If the portable computers in your organization require special device drivers, consider creating separate disk images for your portable computers. Having separate disk images for your portable computers prevents device conflicts and ensures that the appropriate device drivers are installed on both your portable and desktop computers.

In each copy of the worksheet under "Hardware Installed on this Image," record the names of the portable devices the disk image supports and the names of the device driver files that are associated with the devices. You might have to create more copies of the worksheet if you decide to create separate disk images for your portable computers.

You do not need to create separate disk images for legacy (non–Plug and Play) hardware or hardware that requires vendor-specific device drivers; however, you might want to do this if you have a large number of computers that require the same special device drivers and have the same hardware configuration. For example, you might want to create a separate disk image for file servers that have RAID storage devices. Frequently, you have to install vendor-specific drivers for RAID devices, and you have to use a vendor-specific utility to configure them. Having a separate disk image lets you copy a fully configured and optimized system without having to perform any configuration tasks after deployment.

You can use your hardware inventory to identify legacy devices or other devices that require vendor-specific device drivers. In each copy of the worksheet under "Hardware Installed on this Image," record the names of any legacy devices and vendor-specific devices a disk image supports. Also include the names of all files that are associated with the device drivers.

You do not need a separate disk image for each mass storage controller. However, you need to make sure that the appropriate device drivers for a mass storage controller are available on a disk image or on a floppy disk. If a mass storage controller is listed in the device information files that ship with Windows Server 2003 and Windows XP Professional — Machine.inf, Scsi.inf, Pnpscsi.inf, or Mshdc.inf — then the device drivers for it will be available on the disk image. If the mass storage controller is not listed in one of these .inf files, you need to record the name of the mass storage controller under "Hardware Installed on this Image." If the mass storage controller is not listed in the "Mass Storage Controller Worksheet" (ACISYS_2.doc), you also need to record the following information for the mass storage controller under "Hardware Installed on this Image": the Plug and Play device ID, the names of the device driver files, the tag file or disk tag, and the name of the .inf file.