View Full Version : I booted from a USB drive...

07-06-2005, 06:49 PM
From everything I've read, I'm not sure how I managed to do this, but I just booted from a backup to my external Lacie USB drive. I'm using Tiger. Did Apple make booting from USB possible under Tiger?

I just wanted to find out if anyone else has done this so that I can make the partition on my USB drive my regular backup. If this was some kind of fluke, then I'll move my backups to an Iogear Firewire drive, but I'd prefer to continue using the Lacie.

Any ideas how I booted successfully from a USB drive?

07-06-2005, 06:53 PM
Are you *sure* you actually came up on the external drive, as opposed to selecting it and *thinking* you're up on it? You can transparently fall back... check the "root" of each drive in the Finder. The one with "special" icons for /Applications is the boot drive... you might want to try ejecting it, too.

Alternatively, you can look in System Profiler. The drive mounted at / is the boot drive, and each drive will give its mount point in the appropriate drive section.

All current information indicates that USB drives are definitely not supported as boot targets under OSX.

(Note: the IOGEAR drives also have problems under Tiger: a lot of people are having issues due to the non-Oxford chipset used.)

07-07-2005, 01:33 AM
I'll try it again tomorrow when I have more time. For now, here's the evidence I have that I actually booted from the external USB drive:

1) When holding down option at start-up, then external USB drive came up as a boot drive option

2) When I selected it, the computer started up, and the desktop I was looking at had the files and folders that looked like the state of my desktop when I did the backup, not the more recent desktop I had seen just before restarting the computer.

3) I saved a folder to the desktop named "backup desktop test," then re-booted from the internal HD. The newly created folder was not present.

Admittedly, this is the evidence of a novice. Like I said, I will use the checks you suggest tomorrow. Can you explain how to "check the 'root' of each drive in the Finder?" Is there something to look for other than "special" icons in the boot drive? You said "you might want to try ejecting it, too." Is the boot drive "unejectable?"

Finally, when you say that "The drive mounted at / is the boot drive," do you mean that when I go into Apple System Profiler and look at the USB drive, if I have actually booted from it it should simply read:

Mount Point: /

Just want to make sure so that when I pull the rabbit out of the hat again, I know whether it's actually a rabbit.


07-07-2005, 08:29 AM
That all sounds like you booted from it, Steve, but you're the only one I've ever met who has managed this feat. You sure it's not a USB-capable drive and you're not using the FW part of the interface?

(Honestly, I'm not trying to insult you in any way -- we've just never seen this before, and have been told it's not possible by Apple.)

07-07-2005, 05:58 PM
Here's "proof" that I did in fact boot from my USB drive (see below).

It's a strictly USB drive, no mistakin' it. I'm not insulted by your questions. I'm as amazed as you.

I guess my question now is whether I can trust that I will continue to be able to boot from this drive. If so, I'd like to keep my regular bootable backup on it. But I guess if this is a "first ever" then you wouldn't know the answer to that question.

Is there some forum for reporting this sort of thing to Apple? Would the info be useful to them?


Lacie Hard Drive USB:

Capacity: 232.89 GB
Removable Media: Yes
Detachable Drive: Yes
BSD Name: disk2
Version: 0.00
Bus Power (mA): 500
Speed: Up to 480 Mb/sec
Manufacturer: Lacie
OS9 Drivers: Yes
Product ID: 0x0351
Serial Number: 10000E0006578768
S.M.A.R.T. status: Not Supported
Vendor ID: 0x059f
Startup disk:
Capacity: 49.87 GB
Available: 31.97 GB
Writable: Yes
File System: Journaled HFS+
BSD Name: disk2s12
Mount Point: /

07-07-2005, 06:12 PM
Wow. I have no idea why that's working, but I'll try to find out.

07-07-2005, 06:44 PM
Well, I've checked around. The Knowledge Base says, pretty bluntly, not to do this:


It seems that it might work sometimes. I wouldn't rely on it, if I were you. (Of course, you can still restore it using the steps in Section 5 of the User's Guide, but I wouldn't count on being able to boot from it directly.)

What exact Mac do you have? Is it recent?

07-08-2005, 12:30 AM
Well, I've checked around. The Knowledge Base says, pretty bluntly, not to do this...What exact Mac do you have? Is it recent?

OK, I will plan on continuing to backup to the USB drive, but will follow the steps in section 5 to restore from Disk Utility on the install DVD in the event of a catastrophe.

To answer your question about my computer: flatpanel iMac (tray loading CD drive) about two years old: 1 Ghz powerpc G4, 768 MB RAM.

One explanation might be that both times I booted from the external USB drive, I also had my external firewire (without a bootable partition) hooked up. This is the novice in me again, but I am wondering whether the computer detects the firewire drive and the USB drive, and goes ahead and boots from the USB drive thinking it is the firewire.

Lastly, some SuperDuper!-related questions (my apologies for so far taking up your time with hardware issues)...

1) If I do regular backups is there any reason to do a safety clone?
2) The safety clone is useless (if it's on a partition of the internal HD) if the whole HD crashes, right? So the safest backup strategy is to backup to an external drive regularly, yes?
3) I love SuperDuper! (not really a question).


07-08-2005, 04:21 AM
The new Intel-based developer Mac boot from USB but not FireWire... maybe that's why there's half-baked unsupported code for it on current PPC systems?

07-08-2005, 09:35 AM
I don't know, Steve. Surprisingly, there must be some cases where USB booting works. It's news to me, and to the guys at Apple I checked with, but there you go anyway. Clearly, there are problems with it in many situations, so I definitely wouldn't rely on it. (I thought perhaps something had changed in some brand new hardware, but that's not the case here either.)

Anyway -- to get to your questions:

1. It depends, of course. I do regular backups, and run from a Safety Clone, because I install a lot of stuff that could mess up my system. A backup, once restores, restores everything -- including your user files. So, if your backup is a day old, and you need to restore it due to a badly behaved new driver, app, or whatever, you lose a day's work.

With a Safety Clone, you just boot back from the original volume, and lose no work.

2. Yes, it's not a backup, it's a checkpoint of the system and applications. It's not designed for that kind of recovery -- that's what your backup is for.

3. That might be a psychological condition, for which you'll have to seek professional help. ;) (Glad to hear it, though!)

07-08-2005, 09:58 AM
I don't think so, actually. I'm not sure we draw any conclusions at all from the Intel machines, since they're transitional hardware, and far from a 'real' Mac...