Apple's dependence upon third-party software has long been a major weakness of the AppleCare Protection Plan [1]. For years, AppleCare purchasers have complained that the package included a Micromat TechTool Deluxe [2] CD that either wouldn't boot the computer for which AppleCare had been purchased or (worse) would boot it but, when run, would damage the hard disk structure in such a way as to make the data unrecoverable. TechTool revisions have been few and far between and have always lagged behind major operating system and hardware revisions. Nor does Apple communicate with purchasers to let them know of such revisions (at least, they've never communicated with this purchaser).
Current AppleCare contract holders will therefore be happy to learn that Micromat has furnished a new TechTool version (3.1.1) that comes in two flavors, one for Intel-based Macs and another for PowerPC-based Macs. It's available as a free download from Apple [3] (in exchange for the serial number of your AppleCare-registered machine). The download, which is about 200 MB, is a disk image; it can be used to install the software on your computer or to burn a bootable CD.
In addition to support for Intel-based Macs, TechTool Deluxe 3.1.1 can now perform Volume Structure testing of the startup volume, has replaced Diagnostic and Rezero Unit tests, and has added Drive Hardware and Directory Scan options. A software updater is available as a 4.5 MB download [4].
[1]: http://www.apple.com/support/products/
[2]: http://www.micromat.com/index.php?option=com_content&task=view&id=37&Itemid=51
[3]: https://support.apple.com/techtooldeluxe/main?id=dl
[4]: http://www.micromat.com/index.php?option=com_content&task=view&id=166&Itemid=61