An alternative way to create a TechTool Pro 4 eDrive

Jun 01, '07 07:30:00AM

Contributed by: Sven G

Micromat's TechTool Pro 4 (TTP4) hardware and disk utility suite has an interesting feature called the "eDrive" (emergency drive), which is an additional partition containing a mini-OS X installation, from which you can boot to run TechTool Pro 4 and other diagnostic programs. In this way, you don't need to boot from the CD, which is very slow (too slow, one could say).

You can create the eDrive directly from within the TTP4 program, which then dynamically and non-destructively resizes your drive in order to accomodate an extra 6 GB HFS+ partition at the end of the selected drive.

But, the problem is that this process of creating an eDrive is quite unreliable and error-prone: for example, when I tried it (several times), it always ended up with an almost full (99%) mini-partition and an unbootable mini-OS X installation, even with wrong symlinks (/etc, and so on) at the root level and without the mach and mach.sym files--that is, comletely unusable as a second startup drive!

I still use TTP4 4.1.2 (PPC), not the latest Universal 4.5.2 version: having a PPC Power Mac and not having yet bought an Intel Mac, so maybe these problems have been solved with the newer version. (But looking at the Micromat forum, I see many eDrive problems.)

So, I had this additional 6 GB partition sitting at the end of my primary internal hard drive, and wondered, what should I do? Well, obviously, (re)create the eDrive manually, by myself!

So I took the Mac OS X 10.4 Install DVD and installed a minimal version (all optional components deselected) of OS X on the eDrive partition (which I still named eDrive, of course), after reformatting it. It installed about 2 GB of files to install, and then I performed the usual setup, then Software Update to bring the system up to date.

After I rebooted into my "main" partition, the eDrive behaved exactly as if it had been created with TTP4: after some seconds, it automatically unmounted from the Desktop, exactly as an original eDrive; and it is indeed selectable as a bootable eDrive from within TTP4.

There are some advantages in making the eDrive by yourself: for example, you can create only one account (e.g., the Administrator account you use in your main OS X), skip printer drivers, fonts and other optional installations, and so on.

An eDrive created in this way is probably even better than the "official" one (which just gets copied--but often with errors, as said above--from parts of your current Mac OS X install).

[kirkmc adds: I haven't tested this, not having TechTool Pro.]

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