Apple Service Diagnostic 3S123 MacOSX 
Description: This package is used in service centers for the Apple hardware testing.
The image contains two images: a test based on the environment based on the EFI and Mac OS X.
The first - small and can be burnt through to the disc, the second - nearly 6 GB to unpack a dedicated partition on the hard drive (maybe you can burn to a DL-disc, but I have not tried it, and this possibility is not formally specified).
All the extra. Information contained in the pdf inside the image and are urged to familiarize before use.
