Apple Hardware Test - What even?

[Marcello]

So, in case people don't know, in pre-2013 macs there is this feature which runs some hardware tests...
it is accessible by holding down the "d" key when you turn on the mac.

Naturally, there's plenty of information on how to use it/what its for, etc, on the internet.

But after seeing the interface of it,I had some questions regarding what it actually is OS-wise...

When loading, its boot screen is this logo, with an OS 9-style purple progress bar underneath:


And then here's a couple screenshots taken with my phone:





As you can see, this has the Platinum UI used in Mac OS 8/9 & Rhapsody, up to OS X DP2
(I've also seen a different diagnostic utility run on my mac at my local apple-related repair place, what had the platinum UI, with OS9-looking windows)
This is also on an Intel Mac, from 2012.
So the question is, what operating system is underneath this utility?

Visually it hints at Mac OS 9, but seeing as this is an Intel Mac, It is 99.99% likely that that is not the case (Why would Apple port their old, unsupported OS to a completely different platform and then write drivers for it to support all this modern hardware?)
It could be Darwin-based, but if so, what gives with the legacy UI? (The about box says copyright 2000-2012, and 2000 seems to line up with the darwin bit, also the build number also looks MacOSX-ish in nature.)

It could also be it's own thing, written specifically to test the hardware, and if so it would be really interesting to mess around with... (but again what's up with the UI being so old-school?)

Anyways, does anyone have any knowledge concerning the make-up of this tool?

[nickenzi]

I would guess it is just an EFI application.

[ExplicitNuM5]

How about G4's New World ROM? Or even Marklar (first rumors)?

[Marcello]

I would guess it is just an EFI application.

You guessed right it seems, I found some links for a few Intel Mac AHT dmgs from this blogspot page, and then I also found some PowerPC ones on this Apple page

The Intel ones are most definitely EFI applications.


/dev/disk6 & /dev/disk7 -> For Intel Macs | /dev/disk8 -> PPC iBook
At first I saw this and the whole Apple Partition Map thing confused me at first, I didn't think EFI could boot partitions with that scheme, but it seems like Apple's EFI must be able to.


Top 2 Windows -> Intel Mac | Bottom Row -> PPC
What is really interesting is the contents of these. The Intel/EFI ones have a bunch of EFI Drivers, 3 EFI applications (...../.diagnostics/diags.efi, ..../Mac-<variable>/diags.efi, ...../GUI/gui.efi), and have BMP files that make up the GUI.

It seems that the version for PowerPC machines runs something based on Mac OS 9.2.2, then has a bunch of files related the test.

I guess I figured out the answerto my question, however I think I'm gonna try messing with this stuff a bit more now, it seems cool. (A way to use these EFI drivers in a different EFI application would be really cool)

[SoftWitch]

This really is surprising. So EFI can emulate a complete Mac OS UI with some bitmaps? Or is it the UI libraries compiled into these programs and EFI only starts them?

By the way, I've seen these so-called "Copland" UI elements used up to Mac OS X Server 1.x.

[ExplicitNuM5]

The 3A239... That's pre OS X, isn't it?

It's next to "Apple Hardware Test".

[kylemaguire]

my 2007 machine doesn't run it. After researching I found this link on apples website. http://support.apple.com/kb/ht1509

My computer shipped with 10.4 but then came with a 10.5 disc. I'm assuming that the test is on Disk 1. I can't find my Disk 1 but I have Disk 2. I tried booting from it and it didn't work.

Maybe the software worked great with OS X that apple didn't want to update it until 2013. The new Apple Diagnostics looks way better can be run over the internet.

[AriX]

I always wondered this myself. Great investigation, Marcello! I wonder why they wouldn't just update the bitmaps at some point...

Apparently the newest Macs use Apple Diagnostics, which is a heck of a lot more modern-looking:



But my retina MacBook Pro still uses Apple Hardware Test, which looks even worse on the retina display:

The 3A239... That's pre OS X, isn't it?

Presumably that's the build number of the Apple Hardware Test itself, not for some old version of the Mac OS.

[Hoody007]

I recently was at Apple having my Retina MacBook Pro sorted. I asked the Apple Genius about this. Allegedly, the software has more in common with the initial Server build of OS X visually and functionally, but under the hood, it's the same core as Mavericks.

[theirongiant]

The older Apple Hardware Tests were standalone CDs. Nowadays, the Macs can be booted off a local network to run a set of diagnostics. The Apple Store geniuses and any AASP are running a Mac with OS X Server (10.8, 10.9 or 10.10) with NetBoot enabled. These Macs have the "Diagnostic Gateway" installed, which requires Internet access to be able to talk to a server in Cupertino. The whole setup requires an Apple ID with technician access (a GSX account), which means you need to be ACMT certified. An application called Gateway Manager configures the server component that allows use these NetBoot images. You can load as many as you want, but if your Apple ID doesn't check out, or if the server is not connected to the Internet, then the gateway daemon won't run and you cannot boot any of these images.

[abbers]

Nowadays, the Macs can be booted off a local network to run a set of diagnostics. The Apple Store geniuses and any AASP are running a Mac with OS X Server (10.8, 10.9 or 10.10) with NetBoot enabled. These Macs have the "Diagnostic Gateway" installed, which requires Internet access to be able to talk to a server in Cupertino. The whole setup requires an Apple ID with technician access (a GSX account), which means you need to be ACMT certified. An application called Gateway Manager configures the server component that allows use these NetBoot images. You can load as many as you want, but if your Apple ID doesn't check out, or if the server is .

Aha, thanks for the confirmation. I dropped off an iMac at my local Apple store last year after it suffered a failing hard drive and the engineer connected it to a network and (before I could see what keys he had pressed) had already booted the iMac into a really flash-looking diagnostics application. The application correctly detected the failing hard drive in a matter of seconds and could even detect the fact I'd installed third-party RAM.

I've tried every boot-time key combination I know of since then in order to find that same diagnostics application, but never found it. . .

As for the iMac, it took ONE WEEK for Apple to replace the hard drive!

[ExplicitNuM5]

Nice necromancing. But since you are talking about it now, I may as well as talk.

He probably messed up the boot record so you can't boot in. I can do so through Clover as I used to run Hackintoshes, but there you go. He purposely messed up something.

[James]

Nowadays, the Macs can be booted off a local network to run a set of diagnostics. The Apple Store geniuses and any AASP are running a Mac with OS X Server (10.8, 10.9 or 10.10) with NetBoot enabled. These Macs have the "Diagnostic Gateway" installed, which requires Internet access to be able to talk to a server in Cupertino. The whole setup requires an Apple ID with technician access (a GSX account), which means you need to be ACMT certified. An application called Gateway Manager configures the server component that allows use these NetBoot images. You can load as many as you want, but if your Apple ID doesn't check out, or if the server is .

Aha, thanks for the confirmation. I dropped off an iMac at my local Apple store last year after it suffered a failing hard drive and the engineer connected it to a network and (before I could see what keys he had pressed) had already booted the iMac into a really flash-looking diagnostics application. The application correctly detected the failing hard drive in a matter of seconds and could even detect the fact I'd installed third-party RAM.

I've tried every boot-time key combination I know of since then in order to find that same diagnostics application, but never found it. . .

As for the iMac, it took ONE WEEK for Apple to replace the hard drive!

Well, for one, don't bump old posts, but since it's relevant...

Anyway; a simple week? My word. When my iMac's hard drive went belly up years ago, I had to replace it three times before it stuck. A life lesson learned to never use GeekSquad for computer repairs, even if your father works there and knows the guy who works on your computer. Dafuq.