Extracting Hardware Test from installer disk set

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Extracting Hardware Test from installer disk set

My iMac G5's installer disk #1 includes the Apple Hardware Test (AHT) for my model. I cannot clone the DVD to a regular, single layer DVD-R or +R blank because it is too large to fit on one disk. Thus, I would like to make a bootable DVD-R or +R disk with only the AHT volume on it for backup purposes & to cut down on wear & tear on the original disk.

The problem is the AHT volume does not show up as such anywhere except with the Startup Manager (Option key restart), so normal methods for making bootable clones of volumes (like Disk Utility disk master images or with SuperDuper) do not work.

Does anyone have an ideas on how this can be done, or how the volume has been made invisible?

iMac G5/2.0 GHz 17" ALS (Rev B), Mac OS X (10.4.6), 512 MB RAM, Kensington Trackball

Posted on Apr 26, 2006 7:19 AM

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Answer 1

a brody

Level 10

85,314 points

Apr 26, 2006 8:03 AM in response to R C-R

I haven't tried it, but I wonder if it is an issue of visibility? You can force visibility in the Finder with

http://www.bresink.com/osx/TinkerTool.html

I'm not where I can test it right now, though let me know if it works?

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Answer 2

R C-R Author

Level 6

17,794 points

Apr 26, 2006 8:39 AM in response to a brody

Tinkertool doesn't help, nor did I expect it to. The problem is the volume (?) containing AHT is hidden & doesn't show up (AFAIK) at any time other than at startup, when it can be selected with Startup Manager.

Thus, it doesn't matter if Finder is set to display invisible files or not, since it cannot display anything on unmounted volumes.

Basically, I'm assuming AHT is or acts like a separate volume on the DVD, since it shows up that way with Startup Manager. It obviously isn't a normal startup candidate, since it doesn't contain OS X or most likely even a file system, but it must contain some boot loader of some sort, which may be AHT itself, that Open Firmware recognizes as a startup candidate.

I do note that Tinkertool may be of some help in cloning the entire installer disk, assuming a DL DVD+R will work: I have noted the same potential problem with Disk Utility when considering how to make an image of the disk, rather than just the visible "Mac OS X Install Disc 1" volume. Tinkertool allows the hidden option to enable "extended" image conversion choices for disk images. With this option checked, Disk Utility's File -> New -> "Image from Disk 1" gives me an "entire device" image format choice, which I'm hoping will do exactly what it says, although I haven't tried it yet.

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Answer 3

R C-R Author

Level 6

17,794 points

Apr 26, 2006 11:41 AM in response to R C-R

FWIW, I just tried using the "entire device" image format with the installer DVD. This appears to make a complete image of it, & judging by Disk Utility's log entries for MD5 checksums, AHT is partition 4 of the DVD. From the log, there appear to be these partitions:

Driver Descriptor Map : 0 or disk1 (?)
Apple partitionmap : 1 or disk1s1 (The partition scheme)
Apple DriverATAPI : 2 or disk2s2 (A boot driver for ATAPI-connected optical disks, I think)
Apple_HFS : 3 or disk2s3 (This is the "Mac OS X Install Disc 1" volume, the only one with a mount point)
Apple_Boot : 4 or disk2s4 ("Apple Hardware Test" appears after the MD5 checksum)
Apple_Free : 5 or disk2s5 (Some minor free space, I think)

So, it appears that AHT is an "Apple Boot" partition, but not a partition that can be mounted or copied in a normal way. And unfortunately, using the full image as a source in Disk Utility's "Restore" pane doesn't seem to make a complete restore -- at least when I use a small partition on another drive as the destination, the result won't display AHT as a choice with Startup Manager.

What I need is a utility that will work with all partitions, not just mountable ones. If anybody has a clue about such a thing, please let me know about it!

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Answer 4

R C-R Author

Level 6

17,794 points

May 10, 2006 2:28 AM in response to R C-R

I still haven't figured out how to extract AHT from the installer disk but I was (much to my surprise) able to create a functional clone of the entire disk using only a DVD+R DL blank & Disk Utility. For some reason, I thought D.U. lacked support for burning DL disks, but that isn't the case, so it turned out to be as easy as making a CD/DVD Master image of the disk (not just the "Mac OS X Install Disc 1" volume) & burning it to a DL blank.

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