Identifying Architecture of NetBoot Image

By: Richard Glaser - Revised: 2006-12-29 richard


Architecture Specific
NetBoot images can be architecture-specific. With the release of Mac OS X 10.4.4 Server and later, Apple has made NetBoot architecture-aware, supporting either Mac's with a PowerPC or Intel processor. With architecture-specific NetBoot images they can only support either the PowerPC or Intel architecture, but NOT both.

NetBoot Image - Architecture Specific

NetBoot images can also be universal, supporting both architectures, PowerPC and Intel processors. You can use the Mac OS X Server 10.4.7 (Universal) disc to create a universal  NetBoot image, and must use the System Image Utility that comes with Mac OS X Server 10.4.7 or later.

Or you can setup a machine with a universal system, using the Mac OS X Server 10.4.7 (Universal) disc or techniques like using radmind to layering  PowerPC & Intel baseloads to create a universal system. Then you can use Apple's System Image Utility or third-party tools like NetRestore Helper to create the universal image.

Note, officially Apple doesn't support a universal client system, until Mac OS X 10.5. So, it probably isn't worth the additional effort or potential issues to creating a universal client system to deployed to your clients. But, is relatively easy and simplifies NetBoot management to create a universal image to boot PowerPC & Intel clients.

NetBoot Image - Universal

Use Server Admin

One method to identify if a NetBoot image is architecture-specific or universal is using the Server Admin application.
  1. Launch Server Admin
  2. Connect to your NetBoot Server
  3. Select NetBoot from the list of Services for that server, then click Settings.
  4. Next, click the Image pane a check the "Architecture" column for the image.
If the architecture is is Intel or PowerPC then the image is architecture-specific. If the architecture is Universal, then the image is universal.

Server Admin - NetBoot - Images Pane

Use the Finder or Terminal

One method to identify if a NetBoot image is architecture-specific or universal is using Finder or Terminal on the NetBoot Server. Navigate to directory with your NetBoot image.

The syntax is as follows...
cd /Library/NetBoot/NetBootSPn/image.nbi

Where "n" is the volume number. And "image" is the name of the image.

For example...
cd /Library/NetBoot/NetBootSP0/Image_409612271708.nbi

Finder - Go to Folder

Intel NetBoot Images
An Intel NetBoot Image will contain boot files with its i386 directory.

ls -l
total 7227848
-rw-r--r--   1 mac   admin        3253 Dec 27 17:26 NBImageInfo.plist
-rw-rw-r--   1 root  admin  3689938944 Dec 27 17:20 System.dmg
-rw-rw-r--   1 root  admin      170180 Dec 27 17:09 booter
-rw-r--r--   1 mac   admin     4391720 Dec 27 17:20 mach.macosx
-rw-r--r--   1 root  wheel     6147318 Dec 27 17:20 mach.macosx.mkext

PowerPC NetBoot Images
An PowerPC-based NetBoot image all files reside at the root level of the NetBoot image directory.

Universal NetBoot Images
An universal NetBoot image will have both sets of files present in the NetBoot image folder.

Finder - Go to Folder - NetBoot Images - i386